<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-01-19</periodOfReport>

    <issuer>
        <issuerCik>0000921847</issuerCik>
        <issuerName>HUDSON CITY BANCORP INC</issuerName>
        <issuerTradingSymbol>HCBK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001257178</rptOwnerCik>
            <rptOwnerName>FABIANO ANTHONY J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>WEST 80 CENTURY ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PARAMUS</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07652</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2010-01-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>15000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11085</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By ESOP</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9600</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By IRA</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>13.78</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-01-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>45000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2017-01-25</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>45000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>45000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On January 23, 2009 the reporting person received an award of Performance Retention Restricted Stock of 15,000 shares of common stock pursuant to the Hudson City Bancorp, Inc. 2006 Stock Incentive Plan (the &quot;Plan&quot;), which the stockholders approved at the Annual Meeting of Stockholders of Hudson City Bancorp, Inc. held on June 8, 2006.  The award will vest and become directly owned by the reporting person at a rate of 5,000 shares per year on each of January 23, 2010, 2011 and 2012 based on 1) satisfaction of certain corporate measures during the 2009 fiscal year and 2) certification by the Company's Compensation Committee that the measures were satisfied.  The performance criteria for 2009 have been met and on January 19, 2010, certified. Accordingly, 5,000 shares will vest and become directly owned by the reporting person on January 23, 2010.</footnote>
        <footnote id="F2">On January 26, 2007, the reporting person received a grant of Performance Stock Options to purchase 45,000 shares of common stock pursuant to the Plan, which the stockholders approved at the Annual Meeting of Stockholders of Hudson City Bancorp, Inc. held on June 8, 2006.  The options are to vest on January 26, 2010 based on 1) satisfaction, from January 1, 2007 through December 31, 2009, of certain corporate performance measures and 2) certification by the Company's Compensation Committee that the measures were satisfied.  The performance criteria have been met, and on January 19, 2010, certified. Accordingly, 45,000 options will vest and become exercisable by the reporting person on January 26, 2010.</footnote>
    </footnotes>

    <remarks>On  1/23/09 the reporting person received a grant of Performance Stock Options to purchase 45,000 shares of common stock at a price per share of $12.03. These options have a 10-yr term ending 1/22/19 (or earlier in certain circumstances) &amp; become exercisable provided the reporting person remains in continuous service through such date &amp; certain corp. measures tied to return on equity &amp; diluted earnings per share are satisfied on or prior to 1/23/12. On 1/25/08, the reporting person received a grant of Performance Stock Options to purchase 50,000 shares of common stock at a price per share of $15.69.  These options have a 10-yr term ending 1/24/18 (or earlier in certain circumstances) &amp; become exercisable on 1/25/11, provided that the reporting person remains in continuous service through such date &amp; certain corp. performance measures tied to return on equity &amp; diluted earnings per share have been satisfied. Under applicable SEC regulations, these option grants are reportable in Table II of Form 4 only if and when the performance conditions have been satisfied.</remarks>

    <ownerSignature>
        <signatureName>Veronica A. Olszewski, Attorney-in-Fact</signatureName>
        <signatureDate>2010-01-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
