PROSPECTUS




                                1,000,000 Shares

                            IGEN INTERNATIONAL, INC.

                                  COMMON STOCK


         The 1,000,000 shares of Common Stock of IGEN International, Inc.
("IGEN") offered through this prospectus will be sold by the selling
stockholders listed on page 22 of this prospectus.

         The sale of shares offered through this prospectus may be effected by
the selling stockholders from time to time in transactions on the Nasdaq
National Market, in privately negotiated transactions or in a combination of
such methods of sale. The shares may be sold at fixed prices that may change, at
prices prevailing at the time of sale, at prices relating to such prevailing
prices or at negotiated prices. None of the proceeds from this offering will be
received by IGEN.

         IGEN's Common Stock is currently listed on the Nasdaq National Market
under the trading symbol "IGEN." IGEN's principal executive offices are located
at 16020 Industrial Drive, Gaithersburg, Maryland 20877. IGEN's telephone number
is (301) 869-9800.

         Potential investors should consider carefully the risk factors
beginning on page 5 of this prospectus.

         Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined if this
prospectus is truthful or complete. Any representation to the contrary is a
criminal offense.


                  The date of this prospectus is April 5, 2002





                                TABLE OF CONTENTS

About IGEN..............................................................2
The Offering............................................................3
Risk Factors............................................................3
This Prospectus Includes Forward-Looking Information...................19
Where to Find More Information.........................................20
Incorporation of Documents by Reference................................21
Selling Stockholders...................................................22
Use of Proceeds........................................................23
Plan of Distribution...................................................23
Legal Matters..........................................................24
Experts................................................................25
Indemnification........................................................25


         You should rely only on the information contained in this prospectus.
We have not authorized anyone to provide you with information different from
that contained in this prospectus. This prospectus is not an offer to sell or a
solicitation of an offer to buy Common Stock in any jurisdiction where it is
unlawful. The information contained in this prospectus is accurate only as of
the date of this prospectus, regardless of the time of delivery of this
prospectus or of any sale of Common Stock. This preliminary prospectus is
subject to completion prior to this offering.

         Origen, M-Series and Tricorder are trademarks owned by or licensed to
Igen International, Inc. Other trademarks and trade names appearing in this
prospectus are the property of their holders. The domain name and website
address www.igen.com, and all rights thereto, are registered in the name of and
owned by IGEN. The information on our website is not intended to be a part of
this prospectus.

                                   ABOUT IGEN

         We develop and market products that incorporate our proprietary
ORIGEN(R) technology, which permits the detection and measurement of biological
substances. We believe that ORIGEN offers significant advantages over competing
detection methods by providing a unique combination of speed, sensitivity,
flexibility and throughput in a single technology platform. ORIGEN is
incorporated into instrument systems and related consumable reagents, and we
also offer assay development and other services used to perform analytical
testing. Products based on our ORIGEN technology have been developed and sold
for the life science, clinical testing and industrial testing markets.

         We and our corporate collaborators have commercialized numerous product
lines to serve these markets. These sales and placements have been made
predominantly through our license arrangement with Roche Diagnostics GmbH
("Roche"), a leading provider of clinical diagnostic products.

                                       2



         We sell the M-SERIES(TM) System product line for use by pharmaceutical
and biotechnology companies in drug discovery and development. The M-SERIES
System may be used in all phases of drug discovery, including (1) validating
targets identified through genomics, (2) screening of large numbers of compounds
generated through combinatorial chemistry, (3) re-testing and optimization of
lead compounds, and (4) clinical trial testing of drug candidates. We also
provide custom assay development services. We market the M-SERIES System through
our sales, marketing and applications team dedicated to the life science market.

         We have also applied our ORIGEN technology to the rapidly growing
market for testing food and water for disease causing pathogens.

         Our address is 16020 Industrial Drive, Gaithersburg, Maryland 20877,
and our telephone number is (301) 869-9800.

                                  THE OFFERING

         This prospectus relates to 1,000,000 shares of Common Stock that may be
offered for sale by the selling stockholders. On March 11, 2002, we closed a
private placement of the Common Stock to certain accredited investors. As part
of the private placement, we entered into registration rights agreements with
the investors with respect to the purchased shares. We are registering the
Common Stock covered by this prospectus to fulfill our contractual obligations
with respect to these registration rights. Registration of the Common Stock does
not necessarily mean that all or any portion of such stock will be offered for
sale by the selling stockholders.

         We have agreed to bear the expenses of the registration of the Common
Stock under Federal and state securities laws, but we will not receive any
proceeds from the sale of the Common Stock offered under this prospectus.

                                  RISK FACTORS

         INVESTING IN OUR COMMON STOCK IS VERY RISKY. YOU SHOULD BE ABLE TO BEAR
A COMPLETE LOSS OF YOUR INVESTMENT. YOU SHOULD CAREFULLY CONSIDER THE FOLLOWING
FACTORS IN ADDITION TO OTHER INFORMATION CONTAINED ELSEWHERE IN THIS PROSPECTUS
OR INCORPORATED BY REFERENCE INTO THIS PROSPECTUS FROM OUR OTHER SEC FILINGS.
THE RISKS AND UNCERTAINTIES BELOW ARE NOT THE ONLY ONES FACING IGEN BECAUSE WE
ARE ALSO SUBJECT TO ADDITIONAL RISKS AND UNCERTAINTIES NOT PRESENTLY KNOWN TO
US. IF ANY OF THESE RISKS ACTUALLY OCCURS, OUR BUSINESS, FINANCIAL CONDITION,
OPERATING RESULTS, CASH FLOWS AND THE TRADING PRICE FOR OUR STOCK COULD BE
HARMED.

                                       3



         IF THE COMPANIES THAT LICENSE TECHNOLOGY FROM US DO NOT EFFECTIVELY
DEVELOP AND MARKET PRODUCTS BASED ON THAT TECHNOLOGY, OUR REVENUE WOULD BE
ADVERSELY AFFECTED.

         The success of our business depends, in large part, on how effectively
the companies to which we have licensed our technology develop and market that
technology. If these companies do not effectively develop and market products
based on this technology, our revenues would decrease.

         We have licensed our technology to Organon Teknika B.V., Eisai Co.,
Ltd., and Roche Diagnostics GmbH for selected markets and uses. Our license
agreements with each of these companies allow each company to develop products
using our technology and to manufacture and sell those products in selected
markets. In return for the right to use our technology, each of these companies
must pay royalties to us based on revenues they receive from sales of products
based on our technology. These royalties are a significant part of our overall
revenue. For example, they accounted for 52% of our revenue in fiscal year 2001.

         We believe that the companies licensing our technology have economic
incentives to continue marketing products using our technology. However, we
cannot be sure that these companies will diligently and effectively market
products that incorporate the technology we have licensed to them. In addition,
we have brought a lawsuit against Roche, one of our licensees, in part because
we believe Roche has not properly calculated and paid royalties to us and
because we believe Roche has not commercialized our technology as diligently as
our license agreement with Roche requires. See the risk factor immediately below
for a more detailed description of this litigation and the risks it poses to us.
We cannot predict whether similar or other problems will arise with other
companies to whom we license our technology.

         WE ARE SUING THE LARGEST LICENSEE OF OUR TECHNOLOGY, AND THE OUTCOME OF
THAT LITIGATION COULD MATERIALLY ADVERSELY AFFECT OUR REVENUES AND FINANCIAL
CONDITION.

         We have an ongoing lawsuit against Roche, which is the largest licensee
of our technology in terms of royalty income accounting for over 90% of our
royalty income in fiscal 2001. The lawsuit centers on a number of claims we
asserted against Roche in which we allege that they failed to comply with the
terms of our license agreement with them. Under the license agreement, we
granted Roche the exclusive right to manufacture, market and sell
immunodiagnostic products using our patented ORIGEN technology to a designated
field. The license restricts Roche's rights in the Japanese clinical diagnostic
market.

         In February 2002, the United States District Court issued a final order
of judgment in our case against Roche that awarded us $105 million in
compensatory damages and $400 million in punitive damages, confirmed our right
to terminate the Roche license agreement, and directed and commanded Roche to
grant to us for use in our retained fields a license to all improvements
developed by Roche under the agreement, including Roche's Elecsys(R) diagnostics
product line.

                                       4



         The judgment also bars Roche from marketing, selling, placing or
distributing outside of its licensed field any products, including its Elecsys
diagnostics product line, that are based on our ORIGEN(R) technology. We have
voluntarily agreed not to terminate the license agreement until an appellate
court determines that we are entitled to do so. We have already notified Roche
that the license agreement will terminate automatically once the judgment is
affirmed by the Court of Appeals. Once the agreement is terminated, Roche will
be prohibited from commercializing all ORIGEN-based products, including its
Elecsys diagnostics product line, and we will be free to operate, either
independently or with new partners, in the field currently licensed to Roche. We
cannot provide any assurance that we will ultimately prevail in this litigation.
If we do not succeed, our business and revenues could be materially adversely
affected.

         Roche has filed a counterclaim against us in the lawsuit, alleging,
among other things, that we breached the Roche license by permitting Eisai Co.,
Ltd., another of our licensees, to market some ORIGEN-based products in Japan.
The final judgment issued in this case found in our favor and against Roche on
all of Roche's counterclaims, except for one in which we were ordered to pay
$500,000.

         Roche has filed post judgment motions with the district court to set
aside certain aspects of the judgment and we expect that Roche will appeal the
judgment, if not overturned by the district court. During an appeal process,
which we expect to be completed in mid-2003, Roche is obligated to continue to
comply with the terms of the license agreement, including its obligation to
continue to pay us royalties on Roche's sales of royalty-bearing products.

         While we intend to vigorously oppose any appeal filed by Roche, there
can be no assurance that the judgment will not be overturned in whole or in part
or that the district court or an appellate court will not order a new trial on
some or all of the issues in the case. The risks involved in the litigation
include:

     -    The district  court or an appellate  court may modify or overturn some
          or all of the  judgment  favorable  to us  including  the finding that
          Roche materially breached the license agreement,  the scope and extent
          of the  improvements  awarded to us, the  amount of  compensatory  and
          punitive  damages,  or the  favorable  findings  relating  to  Roche's
          counterclaims against us.

     -    The district court or an appellate court could overturn some or all of
          the judgment and order a new trial on those  issues.  For example,  if
          the court orders a new trial on whether or not Roche miscalculated and
          underpaid royalties, breached its duty of good faith and fair dealing,
          or engaged  in unfair  competition  against  us, the amount of damages
          awarded in a new trial could be lower than the amount already  awarded
          to us.

     -    If the court orders a new trial on any of the issues, we might need to
          continue expending significant amounts of money and management time in
          pursuing our claims  against  Roche.  This time and money will then be
          unavailable for use in the development of our business.

                                       5



     -    If the  appellate  court  upheld the  judgment  that Roche  materially
          breached  the  license  agreement,  and  the  license  agreement  were
          terminated, our royalty revenues would suffer unless and until we were
          able to introduce  new  products  and generate  revenues on our own or
          find one or more comparable replacements for Roche.

          There are no assurances that we could find a suitable  replacement for
          Roche or  successfully  introduce  new  products on our own  following
          termination of the license. Our ability to successfully  commercialize
          new products,  including products based on the improvements awarded to
          us in this litigation,  is subject to numerous risks and uncertainties
          including risks relating to:

          -    the need for governmental approvals;

          -    our ability to compete effectively;

          -    our ability to effectively manufacture and market new products;

          -    our ability to attract and retain employees;

          -    our need for additional financing;

          -    our dependence on suppliers; and

          -    the other risks  applicable  to our  business as more  completely
               described below and in our filings with the SEC.

     -    While an appeal  is  pending,  Roche may  divert  its  attention  from
          selling the licensed products that generate  royalties to us and focus
          its  energies  instead to find  alternative  products  to develop  and
          market.

     -    While an appeal is  pending,  Roche may  continue  to market  and sell
          other Roche  products  that  compete with its  ORIGEN-based  products,
          thereby  lowering the royalty  revenues  that we would have  otherwise
          received if Roche had sold more  ORIGEN-based  products instead of its
          other competing products.

 OUR ROYALTY INCOME COULD SUFFER AS A RESULT OF OUR LITIGATION AGAINST HITACHI.

         We are suing Hitachi Ltd. in Japan. Hitachi develops and manufactures
diagnostic equipment based on ORIGEN technology for Roche, to whom we license
our technology. We believe that Hitachi's actions in Japan violate rights that
we originally granted to Eisai Co., Ltd. to develop, manufacture and sell
products using ORIGEN technology to the Japanese clinical diagnostic market. We
have asked the Japanese court to prohibit Hitachi from manufacturing,


                                       6


using or selling in Japan the Elecsys 2010 Instrument, which Hitachi developed
for Roche based on our technology.

         If we lose our lawsuit against Hitachi and Hitachi continues Japanese
manufacturing of products covered by our license with Eisai, Eisai's ability to
sell products based on our technology in Japan could suffer, and the royalty
income we receive from Eisai could decrease as a result. If, on the other hand,
we win the lawsuit against Hitachi, Roche will either have to find a new
manufacturer to make equipment based on ORIGEN technology or make arrangements
for Hitachi to manufacture the equipment outside of Japan. Our royalty income
could suffer if Roche cannot `effectively make alternate arrangements.

         In connection with our ongoing litigation against Roche, Roche has
attempted to sue us for interfering with its contract with Hitachi because we
filed this lawsuit. That claim was dismissed by the district court. If we lose
our lawsuit against Hitachi, Roche may try to bring this claim against us again.
There can be no assurance that we will be able to successfully dismiss this
claim if reinstated.

         FAILURE TO MEET OUR DEBT OBLIGATIONS COULD ADVERSELY AFFECT OUR RESULTS
OF OPERATIONS AND FINANCIAL CONDITION; IN ADDITION, OUR DEBT SERVICE OBLIGATIONS
COULD IMPAIR OUR OPERATING FLEXIBILITY.

         We have a substantial amount of indebtedness, and there is a
possibility that we may be unable to generate cash or arrange financing
sufficient to pay the principal of, interest on and other amounts due in respect
of our indebtedness when due, or in the event any of our indebtedness is
accelerated. In addition, our substantial leverage may require that we dedicate
a substantial portion of our expected cash flow from operations to service our
indebtedness, which would reduce the amount of our expected cash flow available
for other purposes, including working capital and capital expenditures.

         In March 1999, we entered into a debt financing with John Hancock
Mutual Life Insurance Company under a note purchase agreement in which we
received $30 million, and we issued 8.5% senior secured notes due 2006.
Principal and interest installments of $1.7 million are due quarterly through
March 2006. The notes are secured by, among other things, royalty payments and
our right to receive monies due under our license agreement with Roche and a
restricted cash balance account. If we are unable to meet our obligations under
the notes, the note holders could require us to repay the principal amount of,
and accrued interest on, the subordinated convertible debentures, and we may not
have sufficient financial resources or be able to arrange sufficient financing
to make those payments when required.

         In addition, covenants in the note purchase agreement for our 8.5%
senior secured notes require us to comply with annual and quarterly royalty
payment coverage ratios that are tied to royalty payments and debt service.
Termination of the license agreement with Roche would cause the debt payment
obligations to accelerate. This would reduce our cash on hand for other
purposes, including working capital and capital expenditures. There can be no
assurances that we will have sufficient capital to pay the debt, if accelerated
on termination of the license agreement or for any other reason. The note
purchase agreement also contains covenants that


                                       7


limit our ability to take specified actions, including incurring additional
secured debt and amending our license agreement with Roche, which could affect
our ability to resolve issues that are being litigated through an amendment to
the existing license agreement with Roche. These restrictions may limit our
operating flexibility, as well as our ability to raise additional capital.

         In January 2000, we sold $35 million in aggregate principal amount of
5% subordinated convertible debentures due 2005. Unless and until holders of the
debentures convert their debentures into Common Stock, we are required to make
semi-annual interest payments of $875,000 through 2005. If we are unable to meet
our obligations under the subordinated convertible debentures, the debenture
holders could require us to repay the principal amount of, and accrued interest
on, the subordinated convertible debentures, and we may not have sufficient
financial resources or be able to arrange sufficient financing to make those
payments when required.

         WE HAVE A HISTORY OF OPERATING LOSSES, EXPECT TO INCUR FUTURE LOSSES
AND CANNOT BE CERTAIN THAT WE WILL BECOME A PROFITABLE COMPANY.

         We have experienced significant operating losses in most years since
our inception, and we expect those losses to continue. We also have an
accumulated deficit and negative net worth. Our losses have resulted principally
from costs incurred in research and development and from litigation costs,
selling costs and other general and administrative costs. We expect to incur
additional operating losses as a result of increases in expenses for
manufacturing, marketing and sales capabilities, litigation costs and expenses,
research and product development, the transfer and commercialization of
improvements from Roche, general and administrative costs and our share of
losses in Meso Scale Diagnostics ("MSD"). We cannot assure you that we will ever
achieve profitability in the future. Our ability to become profitable in the
future will depend on, among other things, our ability to:

     -    expand the commercialization of our existing products;

     -    upgrade and enhance the M-SERIES product capabilities;

     -    introduce  new products  into the market,  including  products for the
          markets  currently  served by Roche  following  termination of Roche's
          license with us;

     -    develop our marketing capabilities cost-effectively;

     -    develop sales and distribution capabilities cost-effectively; and

     -    establish successful collaborations with corporate partners to develop
          and commercialize products that incorporate our technologies.



                                       8


         OUR QUARTERLY OPERATING RESULTS MAY FLUCTUATE SIGNIFICANTLY, AND THESE
FLUCTUATIONS MAY CAUSE OUR STOCK PRICE TO FALL.

         Our quarterly operating results depend upon:

     -    the volume and timing of orders for M-SERIES or other products;

     -    the timing of instrument deliveries and installations;

     -    the success of M-SERIES upgrades and enhancements;

     -    variations in revenue  recognized  from  royalties and other  contract
          revenues;

     -    our mix of products sold;

     -    whether our instruments are sold to or placed with customers;

     -    the timing of our introduction of new products;

     -    our competitors' introduction of new products;

     -    variations  in expenses we incur in  connection  with the operation of
          our  business,   including  costs  associated  with  the  transfer  of
          improvements   from  Roche  to  us,  research  and  development  costs
          including costs  associated with  developing and  commercializing  new
          products  for the  markets  currently  served by Roche,  and sales and
          marketing costs, including costs for upgrading the M-SERIES products;

     -    our share of losses in MSD;

     -    our manufacturing capabilities; and

     -    the volume and timing of product returns and warranty claims.

         These factors may cause our quarterly operating results to fluctuate
significantly, which in turn, may cause our stock price to fall. In addition,
because our revenues and operating results are volatile and difficult to
predict, we believe that period-to-period comparisons of our results of
operations are not a good indication of our future performance.

         WE MAY NOT BE ABLE TO RAISE SUFFICIENT ADDITIONAL CAPITAL TO
SUCCESSFULLY DEVELOP OUR BUSINESS.

         We need substantial amounts of money to fund our operations. We
currently anticipate that our existing capital resources, together with revenue
from product sales and royalties, will be adequate to fund our operations
through at least the end of our fiscal year ending March 31, 2003. Our access to
funds could be negatively impacted by many factors, including the results of
pending litigation, the volatility of the price of Common Stock, continued
losses from operations,


                                       9


acceleration of debt payment obligations resulting from termination of the
license agreement with Roche and other factors.

         We may need to raise substantial amounts of money to fund a variety of
future activities integral to the development of our business, including the
following:

     -    for  research and  development  in order to  successfully  develop our
          technologies,  including  to develop  new  products  for the  clinical
          diagnostic markets that are currently being served by Roche;

     -    to obtain regulatory approval for some of our products;

     -    to file and  prosecute  patent  applications  in order to protect  our
          technologies;

     -    to respond to innovations that our competitors develop;

     -    to continue to  aggressively  pursue our ongoing  litigations  against
          Roche and Hitachi;

     -    to  retain  qualified  employees,  particularly  in light  of  intense
          competition for qualified scientists and engineers;

     -    to make new  arrangements to market our technology,  including for the
          markets  currently  being served by Roche following the termination of
          our license agreement with Roche;

     -    to continue to fund investments in MSD;

     -    to manufacture products ourselves or through a third party; and

     -    to market  different  products to different  markets,  either  through
          building our own sales and  distribution  capabilities or relying on a
          third party.

         We cannot be certain that we will have access to enough funds to
successfully develop our business.

         We may try to raise necessary additional capital by issuing additional
debt or equity securities. Holders of debt securities would have priority over
our equity holders with respect to the proceeds from the sale of our assets in
the event of liquidation of our business, and any debt financings we obtain may
contain restrictive terms that limit our operating flexibility. If, on the other
hand, we raise additional capital by selling more common or preferred stock, the
holdings of existing stockholders would be diluted. In December 2001, we sold
1,062,947 shares of Common Stock at a purchase price of $29.45 per share; and in
March, 2002, we sold 1,031,726 shares of Common Stock at a purchase price of
$36.81 per share.

                                       10


         If we are unable to raise additional capital, we may have to scale
back, or even eliminate, some programs. Alternatively, we may have to consider
pursuing arrangements with other companies, such as granting licenses or
entering into joint ventures. These arrangements could require that we give up
substantial rights to technology or products.

         WE MAY NOT BE ABLE TO COMPETE EFFECTIVELY AGAINST MORE ESTABLISHED
COMPANIES AND INSTITUTIONS, WHICH COULD ADVERSELY AFFECT OUR BUSINESS.

         We are a relatively young company in a highly competitive industry. We
compete against established companies and research and academic institutions,
and we expect this competition to intensify. Many of these companies and
institutions have one or more competitive advantages over us, including:

     -    more money to invest;

     -    greater   expertise  and  resources  in   developing,   manufacturing,
          marketing and selling products;

     -    a larger, more experienced workforce; and

     -    more  experience  in  obtaining   regulatory   approval  for  clinical
          diagnostic products.

         As a result, we may not be able to compete successfully against our
current or future competitors. This could have a material adverse effect on our
business, financial condition and revenue.

         WE DEPEND ON CONTINUING PRODUCT DEVELOPMENT.

         The market for our products is characterized by rapidly changing
technology, evolving industry standards, the need for updated and effective
technology and new product introduction. Our future success will depend in part
upon our ability to enhance existing products and to develop and introduce new
or enhanced products. There can be no assurance that we will be able to avoid
the obsolescence of our products due to rapid technological change and evolving
industry standards. In general, the development of new or enhanced products is a
complex and uncertain process requiring the accurate anticipation of
technological and market trends as well as precise technological execution. We
have and may continue to experience design, development, implementation and
other difficulties that could delay or prevent our introduction of new or
enhanced products or affect the performance of existing products. These
difficulties and delays have caused, and may continue to cause, our expenses to
increase and our product sales to fluctuate.



                                       11


         WE DEPEND ON HIGHLY TRAINED AND SKILLED EMPLOYEES AND MANAGEMENT, AND
WE CANNOT BE SURE THAT WE WILL BE ABLE TO ATTRACT AND RETAIN SUFFICIENT
PERSONNEL.

         We need to hire additional staff and to retain existing staff, both of
which are difficult in today's competitive marketplace. Because we are a
technology company, we depend heavily on scientists and engineers to develop
products and to build a successful business. Research and development efforts
could suffer if we are not able to hire and retain enough qualified scientists
and engineers.

         We cannot be sure that we will succeed in our hiring and retention
efforts. We compete with other technology companies and research and academic
institutions for experienced scientists. Many of these companies and
institutions have greater resources than we do and thus may be in a better
position to attract desirable candidates.

         In addition to scientists, we will also need to hire managers as the
business grows. We will need managers who are able to address the need for
regulatory, manufacturing and marketing capabilities. If we are not able to hire
managers with these skills, or develop expertise in these areas, our business
prospects could suffer.

         WE DEPEND ON A LIMITED NUMBER OF SUPPLIERS FOR MATERIALS USED IN
MANUFACTURING OUR PRODUCTS, AND ANY INTERRUPTION IN THE SUPPLY OF THOSE
MATERIALS COULD HAMPER OUR ABILITY TO MANUFACTURE PRODUCTS AND MEET CUSTOMER
ORDERS.

         We depend on vendors to supply key materials that we use in our
products. Some of these materials are available only from limited sources. In
the event of a reduction in, interruption of, or degradation in the quality of
the supply of any of our required materials, or an increase in the cost of
obtaining those materials, we would be forced to locate an alternative source of
supply. If no alternative source were available or if an alternative source were
not available on a timely basis or at a reasonable cost or otherwise on
acceptable terms, our ability to manufacture one or more of our products would
be delayed or halted. Any changes in sources of supply may require additional
engineering or technical development in order to ensure consistent and
acceptable performance of the products. If any of these events occur, product
costs may increase, we might be unable to deliver products timely, we could lose
sales as well as customers, and our business would be significantly harmed as a
result.

         WE MUST OBTAIN FDA APPROVAL TO MARKET OUR CLINICAL DIAGNOSTIC PRODUCTS,
WHICH IS OFTEN COSTLY AND TIME CONSUMING, AND IF WE DO NOT OBTAIN THE NECESSARY
APPROVAL OUR BUSINESS PROSPECTS WOULD SUFFER.

         The FDA regulates many areas in which we conduct research and in which
we develop, produce and market products. In particular, we must obtain FDA
approval before we can market clinical diagnostic products such as those we are
currently developing for the patient care market. The approval process is often
costly and time consuming. In addition, we cannot assure


                                       12


you that we will be successful in obtaining FDA approval for any of our
clinical diagnostic products, which would materially adversely affect our
future prospects.

         In order to obtain FDA approval in the United States, we, or the
companies with whom we work, will need to either obtain pre-market application
approval or pre-market notification clearance from the FDA. In order to obtain
pre-market notification clearance, we must submit data from clinical trials
demonstrating that new clinical diagnostic systems are substantially equivalent
to diagnostic systems that the FDA has already approved. If a product is subject
to the substantial equivalence requirement, neither we, nor any of our licensees
can sell that system for clinical use in the United States until the FDA
determines that a new ORIGEN-based system is substantially equivalent to a
previously approved system. Typically, the FDA review process takes 90 days, but
the FDA's review could take longer. In addition, we cannot be sure that we will
be able to demonstrate substantial equivalence for future diagnostic systems.

         If we do not successfully demonstrate substantial equivalence, or if we
are required to obtain pre-market application approval as an initial matter, we
will have to conduct extensive clinical testing of these products, which could
take years to complete. Extensive testing could involve substantial additional
costs and might delay bringing clinical diagnostic products to market, weakening
our competitive position. If we fail to obtain FDA approval for new products
altogether, we will be unable to market our ORIGEN-based systems at all for
clinical use in the United States.

         WE ARE SUBJECT TO EXTENSIVE, ONGOING GOVERNMENT REGULATION, WHICH MAY
INVOLVE SIGNIFICANT COSTS AND MAY RESTRICT OUR ABILITY TO CONDUCT BUSINESS.

         We expect that we may need to spend a substantial amount of money to
comply on an ongoing basis with the regulations of the FDA and other government
agencies. Government agencies, such as the FDA and the Environmental Protection
Agency, regulate manufacturers of diagnostic products and the manufacturing
process itself. The costs of complying with governmental regulations and any
restrictions that government agencies might impose could have a significant
impact on our business. As we increase our manufacturing, these costs will
increase.

         Whether we manufacture products ourselves or contract with another
company to manufacture products based on our technology, the FDA will
continually review and periodically inspect the manufacturing process. If the
FDA were to discover a problem with our products, the manufacturing process or
the manufacturing facility, the FDA could place restrictions on these products
and on the manufacturer. For example, the FDA could require us to recall, or
even totally withdraw, a product from the market or close a manufacturing
facility. In addition to FDA regulations, the process of manufacturing products
is subject to a variety of environmental and safety laws and regulations,
including laws and regulations governing the use and disposal of hazardous
materials. If we fail to comply with these laws or regulations, our business and
financial condition could be materially adversely affected.



                                       13


         WE HAVE LIMITED MANUFACTURING AND MARKETING EXPERIENCE, WHICH PUTS US
AT A COMPETITIVE DISADVANTAGE.

         We lack experience in large-scale manufacturing, which could hamper our
ability to manufacture existing products or new products that we develop. We
have two options to address this issue. First, we could expand our internal
ability to manufacture products. Second, we could contract with a third party to
manufacture for us products based on our technology. If, however, we are unable
to expand our own manufacturing capability or find a suitable manufacturer on
acceptable terms we may be unable to meet demand for existing products and could
be delayed in introducing new products to the market. Failure to meet demand for
existing products or delays in introducing new products could put us at a
competitive disadvantage and could harm our financial condition or our business
prospects.

         We will also need to develop greater selling, marketing and
distribution capabilities. To market clinical diagnostic products directly to
customers, and not through a licensee, we need to develop a substantial sales
force with technical expertise. We also need to establish a distribution system
to support the sales force. Alternatively, we could license or contract with
another company to provide sales and distribution services for products, in much
the same way as we have done with Roche, Eisai and Organon Teknika. We cannot be
sure, however, that we will be able to develop a sufficient sales and
distribution force or that we will be able to find a suitable company to fill
that role for us.

         THE SUCCESS OF OUR BUSINESS DEPENDS ON PATENTS THAT WILL EXPIRE AND
THAT MUST BE ACTIVELY PURSUED AND PROTECTED.

         Our business depends heavily on patents that will expire over time and
may be challenged or circumvented by competitors. Patents allow us to prevent
others, for a time, from using our inventions to compete against us. Our
business success or failure will depend, in part, on our ability to obtain and
maintain adequate patent protection for the ORIGEN technology. We cannot be
certain that current patents or future patents will adequately protect our
technology from being used by our competitors.

         Because there is no consistent policy governing the scope of claims in
medical patents, patent protection is uncertain. Companies may, for example,
challenge and invalidate patents or circumvent valid claims in patents, all of
which could make it necessary for us to defend our patents in litigation.
Litigation over patents poses the following risks to our business:

     -    Litigation  costs  can  be  extremely  high,  which  could  drain  our
          financial resources.

     -    Litigation  over our patents could  discourage  other  companies  from
          working with us to develop and market new products based on technology
          covered by these disputed patents.

     -    If we lose  some  patent  protection  as a result of  litigation,  our
          competitive advantage could be eroded.

                                       14


         OUR BUSINESS WOULD BE HARMED IF WE VIOLATE THE PATENT RIGHTS OF OTHERS.

         Our business success or failure will also depend, in part, on the
patent rights of others. We license technology from other companies and academic
institutions. Because access to this technology is necessary to our business, we
must be certain that we comply with these license agreements. Our business could
be harmed if we breached any of these license agreements and lost the rights to
use this patented technology or if we were unable to renew existing licenses on
acceptable terms or get additional licenses that we may need on acceptable
terms.

         We must also make sure that we do not infringe the patent rights of
others. If we were to infringe others' patent rights we could be exposed to the
following risks:

     -    We could be required to alter, or abandon, our products or processes.

     -    We could be required to obtain a license from the patent holder.

     -    We could lose  customers  that are  reluctant  to  continue  using our
          products or doing business with us.

     -    We could be forced to abandon  development work that we had begun with
          respect to these products.

     -    We could be required to pay damages that could be substantial.

         We cannot be sure that we would be able to alter products or processes
or that we could obtain a license at a reasonable cost, if at all. Our business
could be damaged if we were unable to make necessary alterations or obtain a
necessary license on acceptable terms.

         In addition, we may need to litigate the scope and validity of patents
held by others and such litigation could be a substantial cost for us.

         WE RELY ON TRADE SECRETS AND OTHER INFORMATION THAT CANNOT BE PROTECTED
BY PATENTS, AND WE FACE RISKS THAT THIS INFORMATION WILL BE DISCLOSED TO OTHERS.

         In addition to patents, we also rely in our business on trade secrets,
know-how and other proprietary information. If this information were disclosed
to competitors, our business would suffer. We seek to protect this information,
in part, by entering into confidentiality agreements with licensees, employees
and consultants, which prohibit these parties from disclosing our confidential
information. Despite our entering into these agreements, we cannot be sure that
the agreements will provide adequate protection for our trade secrets, know-how
and other proprietary information or that the information we share with others
during the course of our business will remain confidential. We also cannot be
certain that we would have sufficient legal remedies to correct or compensate
for unauthorized disclosures or sufficient resources to seek redress.



                                       15


         RESTRICTIONS ON HEALTH CARE COSTS AND HEALTH CARE AND INSURANCE
FINANCING PRACTICES COULD LIMIT DEMAND FOR OUR PRODUCTS.

         In the United States and elsewhere, demand for clinical diagnostic
testing is dependent, in part, on consumers' ability to be reimbursed for the
cost of the tests by third-party payors, such as government agencies, health
maintenance organizations and private insurers. Medicaid and other third-party
payors are increasingly challenging the prices charged for medical services,
including clinical diagnostic tests. They are also attempting to contain costs
by limiting their coverage of, and the amount they will reimburse for, clinical
diagnostic tests and other health care products We cannot be certain that
insurers will provide coverage for clinical diagnostic tests in the future.
Without adequate coverage and reimbursement, consumer demand for clinical
diagnostic tests may decrease. Decreased demand would likely cause sales of our
clinical diagnostic products, and sales by our licensees, to fall since fewer
tests would be performed or prices would be lowered, or both. Reduced sales or
royalty income would hurt our business and our business prospects.

         In many foreign markets, governments directly set the prices that
clinical diagnostic companies may charge for their products and services. In the
United States, a number of legislative and regulatory proposals aimed at
changing the health care system have been proposed in recent years. We cannot
predict whether these proposals will be adopted or the effect that these
proposals or managed care efforts may have.

         WE ARE EXPOSED TO PRODUCT LIABILITY RISKS.

         We may not be able to adequately insure against risk of product
liability. As we begin marketing products, we may face product liability for
claims and lawsuits brought by customers. Damages awarded in product liability
cases can be very large. While we have product liability insurance, this
coverage is limited. We cannot assure you that our current product liability
insurance would be adequate to cover us against our potential liabilities or
that we will be able to maintain current levels of product liability insurance
on acceptable terms, if at all. Claims or losses in excess of our current or
future product liability insurance coverage could have a material adverse effect
on our financial condition.

         MANAGEMENT EXERCISES SIGNIFICANT CONTROL OVER IGEN.

         Our management has significant control over IGEN through its stock
ownership. Our officers and directors own, or have the right to purchase, about
28% of Common Stock and our Chief Executive Officer owns approximately 21% of
the Common Stock at March 11, 2002. Our officers and directors have significant
influence over the election of directors and other stockholders actions.



                                       16


         FAILURE TO MANAGE OUR GROWTH COULD ADVERSELY AFFECT OUR BUSINESS.

         We have grown rapidly and expect to continue to grow by hiring new
employees in all areas of our operations, increasing our presence in existing
markets and introducing new products we develop into new potential high-growth
markets. Our growth has placed, and continues to place, a strain on our
management and our operating and financial systems.

         As we grow, our personnel, systems, manufacturing capabilities and
resources, procedures and controls may be inadequate to support future
operations. In order to accommodate the increased operations for sales and
marketing, research and development, facilities and administration, we will need
to hire, train and retain the appropriate personnel. We may also need to improve
our financial and management controls, reporting systems and operating systems.
We may encounter difficulties in developing and implementing other new systems.

         In response to our growth, we have recently implemented a new
enterprise resource planning system in order to automate all of our accounting,
manufacturing, sales and purchasing. If the enterprise resource planning system
fails to operate as we expect or experiences delays or interruptions, our
operations, as well as our ability to manage our increased growth, could be
materially adversely affected.

 PROVISIONS OF OUR GOVERNING DOCUMENTS MAY DETER OTHERS FROM ATTEMPTING TO
ACQUIRE US.

         Our governing documents contain provisions designed to prevent hostile
takeovers, which may limit the ability of stockholders to sell their stock at a
premium in a takeover. According to our governing documents, stockholders can
only act at annual meetings or at special meetings of stockholders. Stockholders
are not allowed to act by written consent. In addition, stockholders are not
allowed to call for a special meeting. Only our board of directors, the chairman
of the board or the president may call a special meeting. These provisions may
make it difficult for stockholders to force us to hold special meetings. These
provisions may also limit the ability of stockholders to consider transactions
that they may want to approve, such as a hostile takeover of us.

         Our governing documents also contain other provisions that could make
it more difficult for a change in control to be effected. Our board of directors
can issue preferred stock and can determine the rights of those preferred
stockholders without the approval of holders of Common Stock. For example, our
board of directors could give preferred stockholders one or more votes on issues
on which holders of Common Stock vote. This could have the effect of diluting
the voting rights of holders of Common Stock, which might further discourage
other companies from trying to acquire us.

         In addition, our certificate of incorporation contains provisions
dividing our board of directors into three classes. Each class serves until the
third succeeding annual meeting, and one class is elected at each annual meeting
of stockholders. As a result, even if our stockholders


                                       17


might prefer to effect a change sooner, it could take at least two annual
meetings of stockholders to change a majority of the members of the board of
directors.

         Furthermore, our certificate of incorporation authorizes, and we have
adopted, a preferred share purchase rights plan, commonly referred to as a
"poison pill." Under the rights plan, we made a dividend distribution to the
stockholders of record on November 6, 1996 of one right to purchase from us one
one-hundredth of a share of our preferred stock for each outstanding share of
Common Stock. The terms of the rights and the circumstances under which they may
be exercised are contained in a rights agreement, which has been filed with the
SEC.

         These terms have been designed to deter hostile takeovers of us, even
though our stockholders might favor a takeover, especially if it were to afford
them an opportunity to sell their stock at a price above the prevailing market
rate.

   OUR STOCK PRICE IS VOLATILE AND COULD DROP PRECIPITOUSLY AND UNEXPECTEDLY.

         Our Common Stock currently trades on The Nasdaq National Market. The
prices of publicly traded stock often fluctuate. The price of our stock may rise
or fall dramatically, even though our business performance has not changed. In
the past, the stock price of technology companies has been especially volatile.
We expect that this will continue to be the case.

         In addition to these fluctuations, an investment in our stock could be
affected by a wide variety of factors that relate to our business and industry,
many of which are outside of our control. For example, the value of Common Stock
could be affected by:

     -    new product introductions;

     -    innovations by competitors;

     -    our competitors' announcements of their financial results;

     -    the  failure  of  our   operating   results  to  meet  or  exceed  the
          expectations of investors and analysts;

     -    changes  in  financial   estimates  and  recommendations  by  security
          analysts;

     -    general economic conditions;

     -    disputes over patents or other proprietary rights;

     -    new or existing litigation, including our litigation with Roche;

     -    publicity;

     -    regulations;

                                       18



     -    market conditions; and

     -    fluctuations in our performance and the performances of our licensees.

         WE DO NOT PLAN TO PAY ANY CASH DIVIDENDS ON OUR COMMON STOCK.

         We have never paid cash dividends on Common Stock. We have no plans to
pay cash dividends in the foreseeable future.

         THE VALUE OF THE COMMON STOCK MAY BE DILUTED IN THE FUTURE.

         Our officers, directors, employees and consultants have options to
purchase a significant aggregate amount of Common Stock. If they exercise their
options and purchase Common Stock, Common Stock will be diluted. In addition, we
currently have preferred stockholders and convertible debenture holders who have
the right to convert their preferred shares and debentures, as the case may be,
to Common Stock. Common Stock would be diluted if these preferred stockholders
or convertible debenture holders decide to convert their securities in the
future. Moreover, Common Stock could be further diluted if we issue additional
Common Stock or securities convertible into Common Stock in the future, which we
may need to do to raise funds for our business. Sales of additional shares of
Common Stock or the conversion of securities into Common Stock could cause the
market price of Common Stock to decrease.

              THIS PROSPECTUS INCLUDES FORWARD-LOOKING INFORMATION

         This prospectus and the documents incorporated in this prospectus by
reference include forward-looking statements under the Securities Act. In
addition from time to time, we or our representatives have made or may make
forward-looking statements orally or in writing. The words "may," "will," "
expect," "anticipate," "believe," "estimate," "plan," "intend" and similar
expressions have been used in this prospectus and the documents incorporated in
this prospectus by reference to identify forward-looking statements. We have
based these forward-looking statements on our current views with respect to
future events and financial performance. Actual results could differ materially
from those projected in the forward-looking statements. These forward-looking
statements are subject to risks, uncertainties and assumptions, including, among
other things:

     -    adverse results in our litigation with Roche;

     -    risks associated with managing and maintaining internal growth;

     -    competition,  including market competition,  competition in the patent
          process  and our  ability to  consummate  contract  negotiations  with
          prospective licensees;

     -    the possible termination of contracts with key licensees;

                                       19



     -    changes in coverages or reimbursement  practices of health maintenance
          organizations and private insurers;

     -    adverse  results in other  litigation and in regulatory  matters,  the
          adoption  of  adverse  legislation  or  regulations,  more  aggressive
          enforcement of existing  legislation or regulations or a change in the
          interpretation of existing legislation or regulations;

     -    dependence on key members of management;

     -    other risks described in this "Risk Factors" section; and

     -    other risks described from time to time in our filings with the SEC.

         We are not obligated to update or revise any forward-looking
statements, whether as a result of new information, future events or otherwise.
All subsequent written and oral forward-looking statements attributable to us or
persons acting on our behalf are expressly qualified in their entirety by the
cautionary statements contained throughout this prospectus and the documents
incorporated in this prospectus by reference. Because of these risks,
uncertainties and assumptions, you should not place undue reliance on these
forward-looking statements.

                         WHERE TO FIND MORE INFORMATION

         We are subject to the reporting requirements of the Securities Exchange
Act of 1934 and file annual, quarterly and current reports, proxy statements and
other information with the SEC. You may read and copy these reports, proxy
statements and other information at the SEC's public reference facilities at
Judiciary Plaza, 450 Fifth Street, N.W., Washington, D.C. 20549 and at Northwest
Atrium Center, 500 W. Madison Street, Suite 1400, Chicago, Illinois 60661-2511.
You can request copies of these documents by writing to the SEC and paying a fee
for the copying cost. Please call the SEC at 1-800-SEC-0330 for more information
about the operation of the public reference facilities. SEC filings are also
available at the SEC's Web site at http://www.sec.gov. Our Common Stock is
listed on the Nasdaq National Market, and you can read and inspect our filings
at the offices of the National Association of Securities Dealers, Inc. at 1735 K
Street, Washington, D.C. 20006.

         This prospectus is only part of a Registration Statement on Form S-3
that we have filed with the SEC under the Securities Act of 1933 and therefore
omits certain information contained in the Registration Statement. We have also
filed exhibits and schedules with the Registration Statement that are excluded
from this prospectus, and you should refer to the applicable exhibit or schedule
for a complete description of any statement referring to any contract or other
document. You may inspect a copy of the Registration Statement, including the
exhibits and schedules, without charge, at the public reference room or obtain a
copy from the SEC upon payment of the fees prescribed by the SEC.


                                       20


                     INCORPORATION OF DOCUMENTS BY REFERENCE

         The SEC allows us to "incorporate by reference" information that we
file with them. Incorporation by reference allows us to disclose important
information to you by referring you to those other documents. The information
incorporated by reference is an important part of this prospectus, and
information that we file later with the SEC will automatically update and
supersede this information. We filed a Registration Statement on Form S-3 under
the Securities Act of 1933 with the SEC with respect to the Common Stock being
offered pursuant to this prospectus. This prospectus omits certain information
contained in the Registration Statement, as permitted by the SEC. You should
refer to the Registration Statement, including the exhibits, for further
information about us and the Common Stock being offered pursuant to this
prospectus. Statements in this prospectus regarding the provisions of certain
documents filed with, or incorporated by reference in, the Registration
Statement are not necessarily complete and each statement is qualified in all
respects by that reference. Copies of all or any part of the Registration
Statement, including the documents incorporated by reference or the exhibits,
may be obtained upon payment of the prescribed rates at the offices of the SEC
listed above. We incorporate by reference the documents listed below and any
future filings made with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the
Securities Exchange Act of 1934 until we sell all of our shares of Common Stock
covered by the registration statement. The documents we are incorporating by
reference are:

     -    Annual Report on Form 10-K for the year ended March 31, 2001;

     -    Quarterly  Reports  on Form  10-Q  for the  quarters  ended  June  30,
          September 30 and December 31, 2001;

     -    Proxy Statement filed July 30, 2001;

     -    Supplement  filed  September 5, 2001 to the Proxy Statement filed July
          30, 2001;

     -    Current Report on Form 8-K, dated August 15, 2001;

     -    Amendment  No. 1 to the Current  Report on Form 8-K,  dated August 15,
          2001;

     -    Current Report on Form 8-K, dated December 7, 2001;

     -    Current Report on Form 8-K, dated January 10, 2002;

     -    Current Report on Form 8-K, dated February 15, 2002;

     -    Current Report on Form 8-K, dated March 8, 2002; and

     -    The  description  of  Common  Stock  contained  in  our   Registration
          Statement  on Form  8-A  filed  with  the  SEC on  December  10,  1996
          including any  amendments or reports filed for the purpose of updating
          such description.



                                       21


         Upon request, we will provide without charge to each person to whom a
copy of this prospectus has been delivered a copy of any information that was
incorporated by reference in the prospectus (other than exhibits to documents,
unless the exhibits are specifically incorporated by reference into the
prospectus). We will also provide upon request, without charge to each person to
whom a copy of this prospectus has been delivered, a copy of all documents filed
by us from time to time with the SEC pursuant to the Securities Exchange Act of
1934. Requests for copies should be directed to:

                           IGEN International, Inc.
                           16020 Industrial Drive
                           Gaithersburg, MD  20877
                           Attention:  George Migausky, Chief Financial Officer
                           Telephone:  (301) 869-9800

         This prospectus is part of a Registration Statement we filed with the
SEC. You should rely only on the information incorporated by reference in or
provided in this prospectus and the Registration Statement. We have not
authorized any other person to provide you with different information. We are
not making an offer of these securities in any state where the offer is not
permitted. You should not assume that the information in this prospectus is
accurate as of any date other than the date on the front of this document.

                              SELLING STOCKHOLDERS

         As part of the private placement that we closed on March 11, 2002, we
entered into registration rights agreements with the investors with respect to
the purchased shares. We are registering the Common Stock covered by this
prospectus to fulfill our contractual obligations with respect to these
registration rights.

         The following table sets forth the names of the stockholders selling
shares of Common Stock in this offering, the number of shares of Common Stock
owned by such selling stockholders as of March 28, 2002 and the number of shares
of Common Stock that may be offered for sale pursuant to this prospectus by such
selling stockholders. In some instances, the shares offered pursuant to this
prospectus may be sold by the pledgees, donees or transferees of or other
successors in interest to the selling stockholders. The selling stockholders
have not held any position, office or other material relationship with IGEN or
any of its affiliates within the past three years other than as a result of the
transactions that resulted in its ownership of shares of Common Stock.

         The shares may be offered from time to time by the selling stockholders
named below. However, the selling stockholders are under no obligation to sell
all or any portion of such shares, nor are the selling stockholders obligated to
sell any such shares immediately pursuant to the Registration Statement. Because
the selling stockholders may sell all or part of their shares, no estimate can
be given as to the number of shares of Common Stock that will be held by the
selling stockholders after termination of any offering made by this prospectus.


                                       22




                                        Common Stock Beneficially Owned After
                                       Offering If All Offered Shares Are Sold
                                        Shares of Common Stock   Common Stock        Number           Percent of
                                          Beneficially Owned        Offered     of Shares Owned       Outstanding
Name of Selling                           Prior to Offering         Hereby       After Offering   Shares Owned After
Stockholder                                                                                            Offering
-------------------------------------- ------------------------- -------------- ----------------- --------------------
                                                                                             
Acqua Wellington Private Placement             560,000              560,000            0                  0%
Fund, Ltd.

Acqua Wellington Opportunity I                 440,000              440,000            0                  0%
Limited


         From time to time the selling stockholders may transfer or donate their
shares to others and upon acquiring the shares, such persons will be deemed to
be selling stockholders for purposes of this prospectus. The number of shares
owned by the selling stockholders in the event of such transfer or donation of
shares will decrease as and when it takes such actions. The plan of distribution
for shares sold hereunder will otherwise remain unchanged, except that the
transferees, donees or other successors will be selling stockholders hereunder.
If IGEN is notified by a selling stockholder that a transferee or a donee
intends to sell more than 500 shares, a supplement to this prospectus will be
filed.

                                 USE OF PROCEEDS

         There will be no proceeds to IGEN from the sale of the shares by the
selling stockholders. Any proceeds from the sale of Common Stock received by the
selling stockholders will be retained by the selling stockholders.

         IGEN will pay substantially all of the expenses incident to the
registration, offering and sale of the shares to the public other than
commissions or discounts of underwriters, broker-dealers or agents and the
expenses of counsel to the selling stockholder. Such expenses are estimated to
be approximately $27,000. IGEN has also agreed to indemnify the selling
stockholders against certain liabilities, including liabilities under the
Securities Act of 1933.

                              PLAN OF DISTRIBUTION

         We are registering the shares of Common Stock on behalf of the selling
stockholders, and IGEN will not receive any proceeds from this offering. The
shares of Common Stock may be sold in one or more transactions at fixed prices,
at prevailing market prices at the time of sale, at prices related to the
prevailing market prices, at varying prices determined at the time of sale, or
at negotiated prices. These sales may be effected at various times in one or
more of the following transactions, or in other kinds of transactions:

                                       23


     o    transactions  on  the  Nasdaq  National  Market  or  on  any  national
          securities  exchange  or  U.S.  inter-dealer  system  of a  registered
          national  securities  association  on which  the  Common  Stock may be
          listed or quoted at the time of sale;

     o    in the over-the-counter market;

     o    in  private  transactions  and  transactions  otherwise  than on these
          exchanges or systems or in the over-the-counter market;

     o    in connection with short sales of the shares;

     o    by pledge to secure debt and other obligations;

     o    through the  writing of options,  whether the options are listed on an
          options exchange or otherwise;

     o    in connection with the writing of non-traded and exchange-traded  call
          options, in hedge transactions and in settlement of other transactions
          in standardized or over-the-counter options; or

     o    through  a  combination  of any of the above  transactions,  or by any
          other legally available means.

         The selling stockholders and their successors, including their
transferees, pledgees or donees or their successors, may sell the Common Stock
directly to purchasers or through underwriters, broker-dealers or agents, who
may receive compensation in the form of discounts, concessions or commissions
from the selling stockholders or the purchasers. These discounts, concessions or
commissions as to any particular underwriter, broker-dealer or agent may be in
excess of those customary in the types of transactions involved.

         In addition, any securities covered by this prospectus which qualify
for sale pursuant to Rule 144 of the Securities Act may be sold under Rule 144
rather than pursuant to this prospectus.

         We entered into registration rights agreements for the benefit of the
selling stockholders to register the Common Stock under applicable Federal and
state securities laws. The registration rights agreements provide for
cross-indemnification of the selling stockholders and us and our respective
directors, officers and controlling persons against specific liabilities in
connection with the offer and sale of the Common Stock, including liabilities
under the Securities Act. We will pay substantially all of the expenses incurred
by the selling stockholders incident to the offering and sale of the Common
Stock.

                                  LEGAL MATTERS

         The validity of the issuance of the Common Stock offered in this
prospectus is being passed upon for us by Kirkpatrick & Lockhart LLP.



                                       24


                                     EXPERTS

         The consolidated financial statements incorporated in this prospectus
by reference from IGEN's Annual Report on Form 10-K for the year ended March 31,
2001 have been audited by Deloitte & Touche LLP, independent auditors, as stated
in their report, which is incorporated herein by reference and have been so
incorporated in reliance upon the report of such firm given upon their authority
as experts in accounting and auditing.

                                 Indemnification

         The Company's Bylaws provide that the Company shall indemnify its
directors and officers to the fullest extent not prohibited by the General
Corporation Law of the State of Delaware; provided, however, that the Company
may modify the extent of such indemnification by individual contracts with its
directors and officers; and, provided, further, that the Company shall not be
required to indemnify any director or officer in connection with any proceeding
(or part thereof) initiated by such person unless (i) such indemnification is
expressly required by law, (ii) the proceeding was authorized by the Board of
Directors of the Company, (iii) such indemnification is provided by the Company,
in its sole discretion, pursuant to the powers vested in the Company by the
General Corporation Law of the State of Delaware, or (iv) such indemnification
is otherwise required by law, by agreement, or by vote of the stockholders or
disinterested directors. Pursuant to these Bylaw provisions, the Company has
entered into indemnity agreements with each of its directors and executive
officers and has obtained director and officer liability insurance in the amount
of $30,000,000.

         Section 145 of the General Corporation Law of the State of Delaware
permits a corporation, under specified circumstances, to indemnify its
directors, employees or agents against expenses (including attorney's fees),
judgments, fines and amounts paid in settlements actually and reasonably
incurred by them in connection with any action, suit or proceeding brought by
third parties by reason of the fact that they were or are directors, officers,
employees or agents of the corporation, if such directors, officers, employees
or agents acted in good faith and in a manner they reasonably believed to be in
or not opposed to the best interests of the corporation and, with respect to any
criminal action or proceeding, had no reason to believe their conduct was
unlawful. In a derivative action, i.e., one by or in the right of the
corporation, indemnification may be made only for expenses actually and
reasonably incurred by directors, officers, employees or agents in connection
with the defense or settlement of an action or suit, and only with respect to a
matter as to which they shall have acted in good faith and in a manner they
reasonably believed to be in or not opposed to the best interests of the
corporation, except that no indemnification shall be made if such person shall
have been adjudged liable to the corporation, unless and only to the extent that
the court in which the action or suit was brought shall determine upon
application that the defendant directors, officers, employees or agents are
fairly and reasonably entitled to indemnity for such expenses despite such
adjudication of liability.

         Article VI of the Company's Certificate of Incorporation states that
directors of the Company will not be personally liable to the Company or its
stockholders for monetary damages


                                       25


for any breach of fiduciary duty as a director, except for liability (i) for
any breach of the director's duty of loyalty to the company or its
stockholders, (ii) for acts or omissions not in good faith or which involve
intentional misconduct or a knowing violation of law, (iii) under Section 174
of the General Corporation Law of the state of Delaware, which makes directors
liable for unlawful dividends or unlawful stock repurchases or redemptions or
(iv) for any transaction from which the director derived an improper personal
benefit. The Company's Certificate of Incorporation further provides that if
the General Corporation Law of the State of Delaware is amended to authorize
corporate action further eliminating or limiting the personal liability of
directors, then the liability of the Company's directors shall be eliminated or
limited to the fullest extent permitted by the General Corporation Law of the
State of Delaware, as so amended.

         We have not authorized any dealer, salesperson or other person to give
any information or represent anything not contained in this prospectus. You must
not rely on any unauthorized information. If anyone provides you with different
or inconsistent information, you should not rely on it. This prospectus does not
offer to sell any shares in any jurisdiction where it is unlawful. The
information in this prospectus is current as of the date shown on the cover
page.

                         [LOGO] IGEN International, Inc.

                        1,000,000 Shares of Common Stock
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                                   PROSPECTUS
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April 5, 2002













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