Ownership Submission
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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(Print or Type Responses)
1. Name and Address of Reporting Person *
GAMCO INVESTORS, INC. ET AL
  2. Issuer Name and Ticker or Trading Symbol
AMPCO PITTSBURGH CORP [AP]
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)
ONE CORPORATE CENTER, 
3. Date of Earliest Transaction (Month/Day/Year)
05/11/2006
(Street)

RYE, NY 10580
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 05/11/2006   S   1,000 D $ 29.197 44,700 I By: Investment Partnership (1)
Common Stock               45,000 D (2)  

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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
GAMCO INVESTORS, INC. ET AL
ONE CORPORATE CENTER
RYE, NY 10580
    X    
GABELLI MARIO J
C/O GAMCO INVESTORS, INC
ONE CORPORATE CENTER
RYE, NY 10580
    X    
GGCP, INC.
140 GREENWICH AVENUE
GREENWICH, CT 06830
    X    

Signatures

 /s/ James E. McKee Attorney-in-Fact for MARIO J. GABELLI and GGCP, INC. and Secretary for GAMCO INVESTORS, INC.   05/12/2006
**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 Reporting Persons have less than a 100% interest in this entity. The amount of securities reported as beneficially owned reflects the total amount of securities held by this entity which is greater than the Reporting Persons indirect pecuniary interests. The Reporting Persons hereby disclaim ownership of these securities in excess of their pecuniary interests.
(2) These securities are owned by GGCP, Inc. Mr. Mario J. Gabelli has less than a 100% interest in GGCP, Inc. and hereby disclaims beneficial ownership of these securities in excess of his pecuniary interest. GAMCO Investors, Inc. has no interest in GGCP, Inc.

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