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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001209191-08-053437.txt : 20080924
<SEC-HEADER>0001209191-08-053437.hdr.sgml : 20080924
<ACCEPTANCE-DATETIME>20080924201041
ACCESSION NUMBER:		0001209191-08-053437
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080916
FILED AS OF DATE:		20080924
DATE AS OF CHANGE:		20080924

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FOUNDRY NETWORKS INC
		CENTRAL INDEX KEY:			0001090071
		STANDARD INDUSTRIAL CLASSIFICATION:	COMPUTER COMMUNICATIONS EQUIPMENT [3576]
		IRS NUMBER:				770431154
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		4980 GREAT AMERICA PARKWAY
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054
		BUSINESS PHONE:		408 207 1700

	MAIL ADDRESS:	
		STREET 1:		4980 GREAT AMERICA PARKWAY
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BROCADE COMMUNICATIONS SYSTEMS INC
		CENTRAL INDEX KEY:			0001009626
		STANDARD INDUSTRIAL CLASSIFICATION:	COMPUTER PERIPHERAL EQUIPMENT, NEC [3577]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1027

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-26689
		FILM NUMBER:		081087449

	BUSINESS ADDRESS:	
		STREET 1:		1745 TECHNOLOGY DRIVE
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95110

	MAIL ADDRESS:	
		STREET 1:		1745 TECHNOLOGY DRIVE
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95110
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>c75482_3x0.xml
<DESCRIPTION>MAIN DOCUMENT DESCRIPTION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0203</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2008-09-16</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001090071</issuerCik>
        <issuerName>FOUNDRY NETWORKS INC</issuerName>
        <issuerTradingSymbol>FDRY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001009626</rptOwnerCik>
            <rptOwnerName>BROCADE COMMUNICATIONS SYSTEMS INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1745 TECHNOLOGY DR.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN JOSE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95110</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4195848</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The purchases reported were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.</footnote>
        <footnote id="F2">This amount excludes as of September 23, 2008, 11,019,223 shares (and certain options that may be exercisable by the option holder), over which Brocade has certain voting rights pursuant to voting agreements with certain directors of Foundry, and with respect to which Brocade disclaims beneficial ownership, as such shares and disclaimer are set forth in Schedule 13D filed on July 31, 2008, as amended from time to time.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Richard Deranleau, Chief Financial Officer and Vice President, Finance</signatureName>
        <signatureDate>2008-09-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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