<SUBMISSION>
<ACCESSION-NUMBER>0001186747-09-000036
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20091103
<FILING-DATE>20091105
<DATE-OF-FILING-DATE-CHANGE>20091105
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>LARSON BRIAN A
<CIK>0001186747
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-12882
<FILM-NUMBER>091162529
</FILING-VALUES>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>BOYD GAMING CORP
<CIK>0000906553
<ASSIGNED-SIC>7990
<IRS-NUMBER>880242733
<STATE-OF-INCORPORATION>NV
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>3883 HOWARD HUGHES PARKWAY
<STREET2>NINTH FLOOR
<CITY>LAS VEGAS
<STATE>NV
<ZIP>89169
<PHONE>7027927200
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>3883 HOWARD HUGHES PARKWAY
<STREET2>NINTH FLOOR
<CITY>LAS VEGAS
<STATE>NV
<ZIP>89169
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>BOYD GROUP
<DATE-CHANGED>19941130
</FORMER-COMPANY>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-11-03</periodOfReport>

    <issuer>
        <issuerCik>0000906553</issuerCik>
        <issuerName>BOYD GAMING CORP</issuerName>
        <issuerTradingSymbol>BYD</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001186747</rptOwnerCik>
            <rptOwnerName>LARSON BRIAN A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3883 HOWARD HUGHES PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2>NINTH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>LAS VEGAS</rptOwnerCity>
            <rptOwnerState>NV</rptOwnerState>
            <rptOwnerZipCode>89169</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-11-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>15155</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>69405</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Employee Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>7.55</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-11-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>67020</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-11-03</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>67020</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>67020</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Reporting Person was awarded 15,155 Restricted Stock Units for no consideration pursuant to the Issuer's 2002 Stock Incentive Plan.  Each Restricted Stock Unit represents a contingent right to receive one share of Issuer common stock upon vesting.  The Restricted Stock Units will vest in full upon the third anniversary of the date of award.  The Restricted Stock Units are subject to the forfeiture and other terms and conditions contained in the award agreement and the 2002 Stock Incentive Plan.</footnote>
        <footnote id="F2">Options granted under the Issuer's 2002 Stock Incentive Plan.  Vesting plan calls for options to become exercisable at the rate of 33.333% per year on the first day of each successive 12 month period commencing one year from grant date.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Brian A. Larson</signatureName>
        <signatureDate>2009-11-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
