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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1. Name and Address of Reporting Person *   Bielasz Jennifer Kathleen 2. Date of Event Requiring Statement (Month/Day/Year) 03/15/2011 3. Issuer Name and Ticker or Trading Symbol ARENA PHARMACEUTICALS INC [ARNA] (Last) (First) (Middle) C/O ARENA PHARMACEUTICALS, INC., 6166 NANCY RIDGE DRIVE 4. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Sr. Dir. of Accounting & Cont. 5. If Amendment, Date Original Filed(Month/Day/Year) (Street) SAN DIEGO, CA 92121 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) Common Stock 7,666 D Â

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
Employee Stock Option (right to buy)	  (1)	01/15/2012	Common Stock	2,500	$ 12.25	D	Â
Employee Stock Option (right to buy)	  (2)	07/19/2012	Common Stock	5,000	$ 11.31	D	Â
Employee Stock Option (right to buy)	  (3)	01/18/2014	Common Stock	5,000	$ 6	D	Â
Employee Stock Option (right to buy)	  (4)	10/08/2014	Common Stock	2,500	$ 4.41	D	Â
Employee Stock Option (right to buy)	  (5)	01/17/2015	Common Stock	4,500	$ 6.16	D	Â
Employee Stock Option (right to buy)	  (6)	01/20/2016	Common Stock	3,000	$ 16.8	D	Â
Employee Stock Option (right to buy)	  (7)	07/28/2016	Common Stock	4,000	$ 10.52	D	Â
Employee Stock Option (right to buy)	  (8)	02/26/2017	Common Stock	6,500	$ 13.5	D	Â
Employee Stock Option (right to buy)	  (9)	03/03/2018	Common Stock	6,000	$ 6.99	D	Â
Employee Stock Option (right to buy)	  (10)	03/17/2019	Common Stock	6,000	$ 4.01	D	Â
Employee Stock Option (right to buy)	  (11)	03/17/2020	Common Stock	9,000	$ 3.25	D	Â

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Bielasz Jennifer Kathleen C/O ARENA PHARMACEUTICALS, INC. 6166 NANCY RIDGE DRIVE SAN DIEGO, CA 92121	Â	Â	  Sr. Dir. of Accounting & Cont.	Â

Signatures

Adam S. Chinnock, as Attorney-in-Fact		03/17/2011
**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)	The options vested in four equal annual installments beginning on January 15, 2003.
(2)	The options vested in four equal annual installments beginning on July 19, 2003.
(3)	The options vested in four equal annual installments beginning on June 1, 2004.
(4)	The options vested in four equal annual installments beginning on October 8, 2005.
(5)	The options were originally for 6,000 shares of common stock, and they vested in four equal annual installments beginning on June 1, 2005. The holder exercised options to purchase 1,500 shares of common stock.
(6)	The options vested in four equal annual installments beginning on January 20, 2007.
(7)	The options vested in four equal annual installments beginning on July 28, 2007
(8)	The options vested in four equal annual installments beginning on February 26, 2008.
(9)	The options vest in four equal annual installments, and are exercisable once vested. The first installment became exercisable on March 3, 2009, the second installment became exercisable on March 3, 2010, the third installment became exercisable on March 3, 2011, and the fourth installment vests on March 3, 2012.
(10)	The options vest in four equal annual installments, and are exercisable once vested. The first installment became exercisable on March 17, 2010, the second installment vests on March 17, 2011, the third installment vests on March 17, 2012, and the fourth installment vests on March 17, 2013.
(11)	The options vest in four equal annual installments beginning on March 17, 2011, and are exercisable once vested.

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