<SUBMISSION>
<ACCESSION-NUMBER>0001025835-08-000085
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20080101
<FILING-DATE>20080319
<DATE-OF-FILING-DATE-CHANGE>20080319
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>MARSH STEPHEN P
<CIK>0001264209
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-15373
<FILM-NUMBER>08699640
</FILING-VALUES>
<MAIL-ADDRESS>
<STREET1>150 N. MERAMEC
<CITY>CLAYTON
<STATE>MI
<ZIP>63105
</MAIL-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>ENTERPRISE FINANCIAL SERVICES CORP
<CIK>0001025835
<ASSIGNED-SIC>6022
<IRS-NUMBER>431706259
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>0907
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>150 NORTH MERAMEC
<STREET2>150 NORTH MERAMEC
<CITY>CLAYTON
<STATE>MO
<ZIP>63105
<PHONE>3147255500
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>150 NORTH MERAMEC
<STREET2>150 NORTH MERAMEC
<CITY>CLAYTON
<STATE>MO
<ZIP>63105
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>ENTERBANK HOLDINGS INC
<DATE-CHANGED>19961024
</FORMER-COMPANY>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-01-01</periodOfReport>

    <issuer>
        <issuerCik>0001025835</issuerCik>
        <issuerName>ENTERPRISE FINANCIAL SERVICES CORP</issuerName>
        <issuerTradingSymbol>EFSC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001264209</rptOwnerCik>
            <rptOwnerName>MARSH STEPHEN P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>150 N. MERAMEC</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ST. LOUIS</rptOwnerCity>
            <rptOwnerState>MO</rptOwnerState>
            <rptOwnerZipCode>63105</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5435</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>25667</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-01-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>495</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>495</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>401 (k)</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Incentive Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>13.05</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2004-10-01</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-08-25</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>8333</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8333</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted Share Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>9448</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9448</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On January 1, 2008, the issuer amended the provisions of its 401 (k) plan by adding a unitized stock fund which holds shares of the issuer's Common Stock.  As a result of such amendments, shares of the issuers Common Stock held in the plan for the benefit of the reporting person were deemed beneficially owned under Section 16.  The reporting person holds units in the stock fund and the shares reported as indirectly held in the 401 (k) plan in this row is an estimate of the number of shares of the issuer's Common Stock held in the unitized stock fund and allocated to the reporting person's account as of 2/28/08.</footnote>
        <footnote id="F2">Effective 10/01/2004 the Board fully vested the oustanding employee and Director stock options.</footnote>
        <footnote id="F3">The RSUs were granted pursuant to the Company's 2002 Stock Incentive Plan.  Each RSU represents the right to receive one share of Common Stock, subject to adjustment as provided in the Grant Agreement.  The May 17 Form 4 and previous Form 4s filed by the reporting person reported a purchase price equal to the fair market value of common stock on the date of the grant,  however no consideration was paid by the reporting person.</footnote>
        <footnote id="F4">The RSUs vest at a rate of 20% annually over five years, subject to continued employment of the reporting person.  Vesting occurs on December 15 of each year, commencing in the calendar year of the grant.  On each vesting date, for each RSU vesting on such date, the reporting person will receive one share of Common Stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Stephen P. Marsh</signatureName>
        <signatureDate>2008-03-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
