<SUBMISSION>
<ACCESSION-NUMBER>0001179110-04-001051
<TYPE>3
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20040105
<FILING-DATE>20040113
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>MATHIAS ANDREW W
<CIK>0001275645
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>3
<ACT>34
<FILE-NUMBER>001-13199
<FILM-NUMBER>04522354
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>SL GREEN REALTY CORP
<STREET2>420 LEXINGTON AVE
<CITY>NEW YORK
<STATE>NY
<ZIP>10170
<PHONE>2125942700
</BUSINESS-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>SL GREEN REALTY CORP
<CIK>0001040971
<ASSIGNED-SIC>6798
<IRS-NUMBER>133956775
<STATE-OF-INCORPORATION>MD
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>420 LEXINGTON AVENUE
<STREET2>ATTN: STEVEN KAHN
<CITY>NEW YORK
<STATE>NY
<ZIP>10170
<PHONE>2125942700
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>420 LEXINGTON AVENUE
<STREET2>ATTN: STEVEN KAHN
<CITY>NEW YORK
<STATE>NY
<ZIP>10170
</MAIL-ADDRESS>
</ISSUER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 3 -
<TEXT>
<XML>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>3</documentType>
<periodOfReport>2004-01-05</periodOfReport>
    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001040971</issuerCik>
        <issuerName>SL GREEN REALTY CORP</issuerName>
        <issuerTradingSymbol>SLG</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001275645</rptOwnerCik>
            <rptOwnerName>MATHIAS ANDREW W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SL GREEN REALTY CORP.</rptOwnerStreet1>
            <rptOwnerStreet2>420 LEXINGTON AVENUE 19TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10170</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>1</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle>Chief Investment Officer</officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable><nonDerivativeHolding><securityTitle><value>common stock</value>
</securityTitle>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>56250</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</nonDerivativeHolding>
</nonDerivativeTable>
<derivativeTable><derivativeHolding><securityTitle><value>Employee Stock Option (Right to Buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>20.8125</value>
</conversionOrExercisePrice>
<exerciseDate><footnoteId id="F4"></footnoteId>
</exerciseDate>
<expirationDate><value>2009-12-23</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>common stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>16666</value>
</underlyingSecurityShares>
</underlyingSecurity>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeHolding>
<derivativeHolding><securityTitle><value>Employee Stock Option (Right to Buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>25.25</value>
</conversionOrExercisePrice>
<exerciseDate><value>2003-10-24</value>
</exerciseDate>
<expirationDate><value>2010-10-24</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>common stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>15000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeHolding>
<derivativeHolding><securityTitle><value>Employee Stock Option (Right to Buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>29.53</value>
</conversionOrExercisePrice>
<exerciseDate><footnoteId id="F1"></footnoteId>
</exerciseDate>
<expirationDate><value>2011-11-09</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>common stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>25000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeHolding>
<derivativeHolding><securityTitle><value>Employee Stock Option (Right to Buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>28.10</value>
</conversionOrExercisePrice>
<exerciseDate><footnoteId id="F2"></footnoteId>
</exerciseDate>
<expirationDate><value>2012-10-10</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>common stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>50000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeHolding>
<derivativeHolding><securityTitle><value>Employee Stock Option (Right to Buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>36.55</value>
</conversionOrExercisePrice>
<exerciseDate><footnoteId id="F3"></footnoteId>
</exerciseDate>
<expirationDate><value>2014-01-01</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>common stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>75000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeHolding>
</derivativeTable>
<footnotes><footnote id="F1">The option vests in three equal installments on December 31, 2004, December 31, 2005 and December 31, 2006.</footnote>
<footnote id="F2">The option vests in equal installments with 10% of the shares vesting on October 10, 2004, 20% of the shares vesting on October 10, 2005, 30% of the shares vesting on October 10, 2006 and the final 50% vesting on October 10, 2007.</footnote>
<footnote id="F3">The option vests in four installments with 10% of the shares vesting on January 1, 2005, 20% of the shares vesting on January 1, 2006, 30% of the shares vesting on January 1, 2007, and the final 40% vesting on January 1, 2008.</footnote>
<footnote id="F4">The option of 25,000 shares vested in three installments, with 17% of the shares vesting on January 1, 2001, 33% of the shares vesting on January 1, 2002 and 50% of the shares vesting on January 1, 2003.</footnote>
</footnotes>
<ownerSignature><signatureName>Andrew Mathias</signatureName>
<signatureDate>2004-01-13</signatureDate>
</ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
