FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * YOUNG ERIC A   2. Issuer Name and Ticker or Trading Symbol DEXCOM INC [DXCM] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O CANAAN PARTNERS, 105 ROWAYTON AVENUE 3. Date of Earliest Transaction (Month/Day/Year) 11/10/2005 (Street) ROWAYTON, CT 06853 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 11/10/2005   S(1)   1,053,000 (2) D $ 13.3 2,040,635 I See Footnote (3)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
YOUNG ERIC A C/O CANAAN PARTNERS 105 ROWAYTON AVENUE ROWAYTON, CT 06853		X
Charmers Landing LLC C/O CANAAN PARTNERS 105 ROWAYTON AVENUE ROWAYTON, CT 06853		X
Stonehenge LLC C/O CANAAN PARTNERS 105 ROWAYTON AVENUE ROWAYTON, CT 06853		X
Waubeeka LLC C/O CANAAN PARTNERS 105 ROWAYTON AVENUE ROWAYTON, CT 06853		X

Signatures

/s/ John D. Lambrech as Attorney in Fact		11/14/2005
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting persons on November 8, 2005.
(2)	Represents 689,715 shares sold Canaan Equity II L.P.; 308,529 shares sold by Canaan Equity II L.P. (QP); and 54,756 shares sold by Canaan Equity II Entrepreneurs LLC. Each of John V. Balen, James C. Furnivall, Stephen L. Green, Deepak Kamra, Gregory Kopchinsky, Guy M. Russo, Eric A. Young, Charmers Landing LLC, Stonehenge LLC and Waubeeka LLC are managers of Canaan Equity Partners II LLC, the general partner or manager, as applicable, of these funds, which individuals may be deemed to have shared voting, investment and dispositive power with respect to these shares, but disclaim beneficial ownership of all shares except to the extent of their respective pecuniary interest therein.
(3)	Consists of 1,336,616 shares held Canaan Equity II L.P.; 597,906 shares held by Canaan Equity II L.P. (QP); and 106,113 shares held by Canaan Equity II Entrepreneurs LLC. Each of John V. Balen, James C. Furnivall, Stephen L. Green, Deepak Kamra, Gregory Kopchinsky, Guy M. Russo, Eric A. Young, Charmers Landing LLC, Stonehenge LLC and Waubeeka LLC are managers of Canaan Equity Partners II LLC, the general partner or manager, as applicable, of these funds, which individuals may be deemed to have shared voting, investment and dispositive power with respect to these shares, but disclaim beneficial ownership of all shares except to the extent of their respective pecuniary interest therein.

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