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 *   Feringa Thomas David 2. Date of Event Requiring Statement (Month/Day/Year) 05/30/2012 3. Issuer Name and Ticker or Trading Symbol F5 NETWORKS INC [FFIV] (Last) (First) (Middle) 401 ELLIOTT AVENUE WEST 4. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) EVP, World Wide Sales 5. If Amendment, Date Original Filed(Month/Day/Year) (Street) SEATTLE, WA 98119 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 170 D Â

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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
Restricted Stock Units (1)	08/01/2012(2)	  (3)	Common Stock	591	$ 0	D	Â
Restricted Stock Units (1)	08/01/2012(4)	  (3)	Common Stock	3,578	$ 0	D	Â

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Feringa Thomas David 401 ELLIOTT AVENUE WEST SEATTLE, WA 98119	Â	Â	  EVP, World Wide Sales	Â

Signatures

/s/ Jeffrey A. Christianson by Power of Attorney		05/31/2012
**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)	Each Restricted Stock Unit represents a contingent right to receive one share of F5 Networks, Inc. Common Stock on the vest date.
(2)	The August 2, 2010 award of 4,726 service-based Restricted Stock Units vests in eight equal quarterly increments beginning November 1, 2010. August 1, 2012 is the first and final vest date for the 591 Restricted Stock Units outstanding under this grant.
(3)	If the reporting person continues to serve as an officer of the Company on the vest date, the corresponding number of shares of Common Stock of F5 Networks, Inc. will be issued to the reporting person on the vest date.
(4)	The August 1, 2011 award of 5,724 service-based Restricted Stock Units vests in eight equal quarterly increments beginning November 1, 2011. August 1, 2012 is the first of the five remaining vest dates for the 3,578 Restricted Stock Units outstanding under this grant.

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