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 *
Shah Gautam
   2. Issuer Name and Ticker or Trading Symbol
ACHILLION PHARMACEUTICALS INC [ACHN] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
SVP and Chief Compliance Ofc.
(Last)
(First)
(Middle)
C/O ACHILLION PHARMACEUTICALS, 300 GEORGE STREET		 3. Date of Earliest Transaction (Month/Day/Year)
04/15/2011
(Street)

NEW HAVEN, CT 06511		 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
Common Stock 04/15/2011   M   4,000 A $ 1.6 7,125 D  
Common Stock 04/15/2011   M   2,000 A $ 1.6 9,125 D  
Common Stock 04/15/2011   M   5,000 A $ 3.28 14,125 D  
Common Stock 04/15/2011   S   11,000 D $ 6.6044 (1) 3,125 D  

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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
Employee Stock Option (Right to Buy) $ 1.6 04/15/2011   M     4,000   (2) 05/26/2014 Common Stock 4,000 $ 0 3,875 D  
Employee Stock Option (Right to Buy) $ 1.6 04/15/2011   M     2,000   (3) 12/16/2014 Common Stock 2,000 $ 0 2,250 D  
Employee Stock Option (Right to Buy) $ 3.28 04/15/2011   M     5,000   (4) 12/18/2019 Common Stock 5,000 $ 0 22,860 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Shah Gautam
C/O ACHILLION PHARMACEUTICALS
300 GEORGE STREET
NEW HAVEN, CT 06511		       SVP and Chief Compliance Ofc.  

Signatures

 /s/ Gautam Shah   04/18/2011
**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 price in Column 4 is a weighted average price. The actual sale prices for these transactions ranged from $6.48 to $6.77. The reporting person will provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.
(2) This option was granted on May 26, 2004 and vested over a four year period with 25% of the shares vesting on the first anniversary of the date of grant and an additional 6.25% vesting at the end of each three-month period thereafter.
(3) This option was granted on December 16, 2004 and vested over a four year period with 25% of the shares vesting on the first anniversary of the date of grant and an additional 6.25% vesting at the end of each three-month period thereafter.
(4) This option was granted on December 18, 2009 and vests over a four year period with 25% of the shares vesting on the first anniversary of the date of grant and an additional 6.25% vesting at the end of each three-month period thereafter.
 
Remarks:
The transactions reported on this Form 4 were executed pursuant to a Rule 10b5-1 trading plan adopted by Mr. Shah on December 17, 2010.

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