<SUBMISSION>
<ACCESSION-NUMBER>0001179110-04-005601
<TYPE>4/A
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20040203
<FILING-DATE>20040308
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>HUGHES GREGORY F
<CIK>0001124464
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4/A
<ACT>34
<FILE-NUMBER>001-13199
<FILM-NUMBER>04655681
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>1301 AVENUE OF THE AMERICAS
<CITY>NEW YORK
<STATE>NY
<ZIP>10019
</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>4/A
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4/A -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2004-02-03</periodOfReport>

    <dateOfOriginalSubmission>2004-02-05</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001040971</issuerCik>
        <issuerName>SL GREEN REALTY CORP</issuerName>
        <issuerTradingSymbol>SLG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001124464</rptOwnerCik>
            <rptOwnerName>HUGHES GREGORY F</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 Financial Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-02-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>22500</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>22500</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Employee Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>43.25</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-02-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2014-02-03</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>100000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>100000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Not Applicable</footnote>
        <footnote id="F2">Due to a clerical error in the original form 4 filing, the amount of shares acquired was inadverantly stated as 22550, when in fact the actual amount of shares acquired is 22500.  All other information on the original filing is correct.</footnote>
        <footnote id="F3">The option vests in five installments with 15% of the shares vesting on February 3, 2005, 15% vesting on February 3, 2006, 20% vesting on February 3, 2007, 20% vesting on February 3, 2008, and the final 30% vesting on February 3, 2009.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Gregory F. Hughes</signatureName>
        <signatureDate>2004-03-08</signatureDate>
    </ownerSignature>
</ownershipDocument>

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