-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 AQRSJn7uAEV1yycyhwiUDRj05FkFjbjGlqgUbgv1yPsGFETDVll0ltdPfWu0wWWe
 XWPgt6LSda9i8kzZOSe2Gg==

<SEC-DOCUMENT>0001209191-09-039268.txt : 20090805
<SEC-HEADER>0001209191-09-039268.hdr.sgml : 20090805
<ACCEPTANCE-DATETIME>20090805194751
ACCESSION NUMBER:		0001209191-09-039268
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20090803
FILED AS OF DATE:		20090805
DATE AS OF CHANGE:		20090805

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Rodriguez John Edward
		CENTRAL INDEX KEY:			0001342166

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-26041
		FILM NUMBER:		09989614

	MAIL ADDRESS:	
		STREET 1:		C/O F5 NETWORKS, INC.
		STREET 2:		401 ELLIOTT AVE. WEST
		CITY:			SEATTLE
		STATE:			WA
		ZIP:			98119

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			F5 NETWORKS INC
		CENTRAL INDEX KEY:			0001048695
		STANDARD INDUSTRIAL CLASSIFICATION:	COMPUTER COMMUNICATIONS EQUIPMENT [3576]
		IRS NUMBER:				911714307
		STATE OF INCORPORATION:			WA
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		401 ELLIOT AVE WEST
		STREET 2:		STE 500
		CITY:			SEATTLE
		STATE:			WA
		ZIP:			98119
		BUSINESS PHONE:		2062725555

	MAIL ADDRESS:	
		STREET 1:		401 ELLIOT AVE WEST
		STREET 2:		STE 500
		CITY:			SEATTLE
		STATE:			WA
		ZIP:			98119

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	F5 LABS INC
		DATE OF NAME CHANGE:	19990305
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-08-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001048695</issuerCik>
        <issuerName>F5 NETWORKS INC</issuerName>
        <issuerTradingSymbol>FFIV</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001342166</rptOwnerCik>
            <rptOwnerName>Rodriguez John Edward</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O F5 NETWORKS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>401 ELLIOTT AVE. WEST</rptOwnerStreet2>
            <rptOwnerCity>SEATTLE</rptOwnerCity>
            <rptOwnerState>WA</rptOwnerState>
            <rptOwnerZipCode>98119</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Sr.VP,Chief Accounting Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.00</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-08-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>40000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2009-11-01</value>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-08-03</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>40000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>40000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Fifty percent (50%) of the aggregate number of RSUs in the grant vest in equal quarterly increments over two years, until such portion of the grant is fully vested on August 1, 2011. Twenty five percent (25%) of the grant is subject to a quarterly performance vesting schedule for the period beginning August 3, 2009 through August 1, 2010, based on the Company achieving quarterly revenue and EBITDA targets during the period beginning with the fourth quarter of fiscal year 2009 through the third quarter of fiscal year 2010.  The remaining twenty five percent (25%) is subject to the Company meeting specified performance criteria for a twelve month period in fiscal years 2010 and 2011 to be set by the Compensation Committee of the Company's Board of Directors.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jeffrey A. Christianson by
Power of Attorney</signatureName>
        <signatureDate>2009-08-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24.4_296204
<SEQUENCE>2
<FILENAME>poa.txt
<DESCRIPTION>POA DOCUMENT
<TEXT>
POWER OF ATTORNEY


	 The undersigned hereby constitutes and appoints Jeffrey A. Christianson or
Scot Rogers, or either of them, as the undersigned's true and lawful
attorney-in-fact to:
(1)        execute for and on behalf of the undersigned, in the undersigned's
capacity as an officer and/or director of F5 Networks, Inc. (the "Company"),
Forms 3, 4, and 5 in accordance with Section 16(a) of the Securities Exchange
Act of 1934 and the rules thereunder;
(2)        do and perform any and all acts for and on behalf of the undersigned
which may be necessary or desirable to complete and execute any such Form 3, 4,
or 5, complete and execute any amendment or amendments thereto, and timely file
such form with the United States Securities and Exchange Commission and any
stock exchange or similar authority; and
(3)        take any other action of any type whatsoever in connection with the
foregoing which, in the opinion of such attorney-in-fact, may be of benefit to,
in the best interest of, or legally required by, the undersigned, it being
understood that the documents executed by such attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such form and shall
contain such terms and conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion.
	The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney-in-fact, or such
attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be
done by virtue of this power of attorney and the rights and powers herein
granted.  The undersigned acknowledges that the foregoing attorneys-in-fact, in
serving in such capacity at the request of the undersigned, are not assuming,
nor is the Company assuming, any of the undersigned's responsibilities to comply
with Section 16 of the Securities Exchange Act of 1934.

         This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4, and 5 with respect to the
undersigned's holdings of and transactions in securities issued by the Company,
unless earlier revoked by the undersigned in a signed writing delivered to the
foregoing attorneys-in-fact.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of this 1st day of May, 2007.


/s/ John Edward Rodriguez
John Edward Rodriguez


</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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