<SUBMISSION>
<ACCESSION-NUMBER>0001246360-09-000145
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20090108
<FILING-DATE>20090109
<DATE-OF-FILING-DATE-CHANGE>20090109
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>CADENCE DESIGN SYSTEMS INC
<CIK>0000813672
<ASSIGNED-SIC>7372
<IRS-NUMBER>770148231
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1229
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>2655 SEELY ROAD BLDG 5
<CITY>SAN JOSE
<STATE>CA
<ZIP>95134
<PHONE>4089431234
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>555 RIVER OAKS PARKWAY
<CITY>SAN JOSE
<STATE>CA
<ZIP>95134
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>ECAD INC /DE/
<DATE-CHANGED>19880609
</FORMER-COMPANY>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>TAN LIP BU
<CIK>0001008463
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-10606
<FILM-NUMBER>09519370
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>ONE CALIFORNIA STREET
<STREET2>SUITE 2800
<CITY>SAN FRANCISCO
<STATE>CA
<ZIP>94111
<PHONE>415-765-7100
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>ONE CALIFORNIA STREET 28TH FLOOR
<CITY>SAN FRANCISCO
<STATE>CA
<ZIP>94111
</MAIL-ADDRESS>
<FORMER-NAME>
<FORMER-CONFORMED-NAME>TAN LIP BU ET AL
<DATE-CHANGED>19960217
</FORMER-NAME>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-01-08</periodOfReport>

    <notSubjectToSection16>false</notSubjectToSection16>

    <issuer>
        <issuerCik>0000813672</issuerCik>
        <issuerName>CADENCE DESIGN SYSTEMS INC</issuerName>
        <issuerTradingSymbol>CDNS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001008463</rptOwnerCik>
            <rptOwnerName>TAN LIP BU</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2655 SEELY AVENUE, BLDG 5</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN JOSE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95134</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>President and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>51000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-01-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>300000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>300000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Non-Qualified Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.12</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-01-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>900000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2016-01-08</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>900000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>900000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">One quarter of the restricted stock granted to the reporting person will vest on January 8, 2010 and on January 8th of each of the trhee succeeding years, subject to the achievement of performance criteria and certain other conditions.</footnote>
        <footnote id="F2">Stock option was granted on January 8, 2009 and vests at a rate of 225,000 shares on January 8, 2010 and 18,750 shares each month thereafter.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>James J. Cowie, Attorney-in-Fact for Lip-Bu Tan</signatureName>
        <signatureDate>2009-01-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
