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 * SUN ANTHONY   2. Issuer Name and Ticker or Trading Symbol COGNEX CORP [CGNX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O VENROCK, 3340 HILLVIEW AVENUE 3. Date of Earliest Transaction (Month/Day/Year) 12/15/2009 (Street) PALO ALTO, CA 94304 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ 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

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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

Stock Option (right to buy)

$ 25.595

12/15/2009

D

10,000

12/31/2004

01/22/2016

Common Stock

10,000

$ 3.17 (1)

0

D

Stock Option (right to buy)

$ 31.94

12/15/2009

D

7,500

(2)

02/25/2014

Common Stock

7,500

$ 1.89 (3)

0

D

Stock Option (right to buy)

$ 25.02

12/15/2009

D

7,500

(4)

01/10/2015

Common Stock

7,500

$ 2.79 (5)

0

D

Stock Option (right to buy)

$ 29.38

12/15/2009

D

7,500

(6)

01/30/2016

Common Stock

7,500

$ 1.85 (7)

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
SUN ANTHONY C/O VENROCK 3340 HILLVIEW AVENUE PALO ALTO, CA 94304	X

Signatures

/s/ Anthony Sun		12/17/2009
**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)	On December 15, 2009, the Issuer cancelled, pursuant to the Issuer's offer to purchase certain outstanding stock options for cash, a stock option granted to Mr. Sun on January 22, 2001. Mr. Sun received $31,700 as consideration for the cancellation.
(2)	The option vested in four equal annual installments beginning on January 1, 2005.
(3)	On December 15, 2009, the Issuer cancelled, pursuant to the Issuer's offer to purchase certain outstanding stock options for cash, a stock option granted to Mr. Sun on February 25, 2004. Mr. Sun received $14,175 as consideration for the cancellation.
(4)	The option vested in four equal annual installments beginning on January 1, 2006.
(5)	On December 15, 2009, the Issuer cancelled, pursuant to the Issuer's offer to purchase certain outstanding stock options for cash, a stock option granted to Mr. Sun on January 10, 2005. Mr. Sun received $20,925 as consideration for the cancellation.
(6)	The option vests in four equal annual installments beginning on January 1, 2007.
(7)	On December 15, 2009, the Issuer cancelled, pursuant to the Issuer's offer to purchase certain outstanding stock options for cash, a stock option granted to Mr. Sun on January 30, 2006. Mr. Sun received $13,875 as consideration for the cancellation.

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