<SUBMISSION>
<ACCESSION-NUMBER>0001249323-05-000033
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20050520
<FILING-DATE>20050524
<DATE-OF-FILING-DATE-CHANGE>20050524
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>NETWORK APPLIANCE INC
<CIK>0001002047
<ASSIGNED-SIC>3572
<IRS-NUMBER>770307520
<STATE-OF-INCORPORATION>CA
<FISCAL-YEAR-END>0430
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>495 EAST JAVA DR
<CITY>SUNNYVALE
<STATE>CA
<ZIP>94089
<PHONE>4088226000
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>495 EAST JAVA DR
<CITY>SUNNYVALE
<STATE>CA
<ZIP>94089
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>WARMENHOVEN DANIEL J
<CIK>0001197637
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-27130
<FILM-NUMBER>05853692
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>495 E. JAVA DRIVE
<CITY>SUNNYVALE
<STATE>CA
<ZIP>94089
</BUSINESS-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgardoc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-05-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001002047</issuerCik>
        <issuerName>NETWORK APPLIANCE INC</issuerName>
        <issuerTradingSymbol>NTAP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001197637</rptOwnerCik>
            <rptOwnerName>WARMENHOVEN DANIEL J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>495 EAST JAVA DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SUNNYVALE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94089</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-05-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>25000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>30</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3820260</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Trust</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>42490</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>970000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Lmtd Ptnrshp2</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>170</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Spouse</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1806500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Trust1</value>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>85800</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Trust2</value>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The sale(s) reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 18, 2004.</footnote>
        <footnote id="F2">Shares held in trust by Daniel J. Warmenhoven &amp; Charmaine A. Warmenhoven, trustees to The Warmenhoven 1987 Revocable Trust UTA dated 12/16/87, as amended.</footnote>
        <footnote id="F3">Shares held by Warmenhoven Ventures LP, a limited partnership of which the Warmenhoven Management Trust is the general partner, of which the reporting person and his wife are the trustees.  Reporting person disclaims beneficial ownership of such shares except to the extent of his pecuniary interest therein.</footnote>
        <footnote id="F4">Shares held by Charmaine A. Warmenhoven, Mr. Warmenhoven's spouse, as separate property.  Reporting person disclaims beneficial ownership of such shares.</footnote>
        <footnote id="F5">Shares held in trust by Richard A. Andre, trustee to The Warmenhoven 1995 Children's Trust, under trust agreement dated 5/1/95.  Reporting person disclaims beneficial ownership of such shares.</footnote>
        <footnote id="F6">Shares held in trust by Richard A. Andre, trustee to The Daniel J. Warmenhoven 1991 Children's Trust.  Reporting person disclaims beneficial ownership of such shares.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: Janice Mahoney by Power of Attorney  For: Daniel J. Warmenhoven</signatureName>
        <signatureDate>2005-05-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
