<SUBMISSION>
<ACCESSION-NUMBER>0001246360-09-000590
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20090205
<FILING-DATE>20090209
<DATE-OF-FILING-DATE-CHANGE>20090209
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>Modi Nimish Harsukh
<CIK>0001448998
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-10606
<FILM-NUMBER>09582776
</FILING-VALUES>
<BUSINESS-ADDRESS>
<PHONE>4084738305
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>2655 SEELY AVENUE, BLDG. 5
<CITY>SAN JOSE
<STATE>CA
<ZIP>95134
</MAIL-ADDRESS>
</REPORTING-OWNER>
<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>
<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>2009-02-05</periodOfReport>

    <notSubjectToSection16>false</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001448998</rptOwnerCik>
            <rptOwnerName>Modi Nimish Harsukh</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>false</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>Sr. Vice President - R&amp;D</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11741</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held by Trust</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-02-05</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>30000</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>61531</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F4"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Non-Qualified Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.2</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-02-05</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>200000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2016-02-05</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>200000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>200000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">These securities are held by The Modi Family Revocable Trust dated 2/14/2007, with Nimish Modi and Parul Modi as trustees.</footnote>
        <footnote id="F2">Reflects a correction of an administrative error contained in the Form 3 filed on November 6, 2008, which included 25,500 shares held directly by the reporting person.</footnote>
        <footnote id="F3">Incentive Stock Award vests every 6 months over a 3-year term, subject to the achievement of certain performance criteria.</footnote>
        <footnote id="F4">Beneficial ownership includes 6,031 shares of common stock acquired by the reporting person through the Cadence Design Systems, Inc. Employee Stock Purchase Plan on January 30, 2009.  Also reflects an increase in direct ownership per Footnote 2 above.</footnote>
        <footnote id="F5">Stock Option vests at a rate of 1/48th per month.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>James J. Cowie, Attorney-in-Fact for Nimish H. Modi</signatureName>
        <signatureDate>2009-02-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
