FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF 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 *   GILEAD SCIENCES INC 2. Date of Event Requiring Statement (Month/Day/Year) 10/25/2006 3. Issuer Name and Ticker or Trading Symbol ACHILLION PHARMACEUTICALS INC [ACHN] (Last) (First) (Middle) 333 LAKESIDE DRIVE 4. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) 5. If Amendment, Date Original Filed(Month/Day/Year) (Street) FOSTER CITY, CA 94404 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 Beneficially Owned

1.Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series C-1 Convertible Preferred Stock	  (1)	  (2)	Common Stock	370,494 (3) (4)	$ (3)	D	Â
Series C-2 Convertible Preferred Stock	  (1)	  (2)	Common Stock	745,345 (3) (4)	$ (3)	D	Â

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
GILEAD SCIENCES INC 333 LAKESIDE DRIVE FOSTER CITY, CA 94404	Â	  X	Â	Â

Signatures

/s/ John F. Milligan, Executive Vice President and Chief Financial Officer		10/25/2006
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(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)	These shares will automatically convert into common stock upon the closing of the issuer's initial public offering of common stock.
(2)	Not applicable.
(3)	Reflects a 1-for-8 reverse stock split, which became effective on October 24, 2006. Upon the closing of the issuer's initial public offering, each share of Series C-1 Convertible Preferred Stock will convert into approximately 0.149 shares of common stock and each share of Series C-2 Convertible Preferred Stock will convert into approximately 0.125 shares of common stock.
(4)	Includes shares of preferred stock issued as a dividend which will be paid upon the conversion of the preferred stock.

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