-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 NJmZv8fUiWZWAhbMtGGW3gmjCScO4I3zObZ7m57qpaqwOLEH7YU1J0suCeQzyV/j
 JUtghFCdTiZh0/bgM7KxIg==

<SEC-DOCUMENT>0001266576-10-000017.txt : 20100311
<SEC-HEADER>0001266576-10-000017.hdr.sgml : 20100311
<ACCEPTANCE-DATETIME>20100310200101
ACCESSION NUMBER:		0001266576-10-000017
CONFORMED SUBMISSION TYPE:	D/A
PUBLIC DOCUMENT COUNT:		1
ITEM INFORMATION:		Rule 506
ITEM INFORMATION:		Investment Company Act Section 3(c)
ITEM INFORMATION:		Section 3(c)(7)
FILED AS OF DATE:		20100311
DATE AS OF CHANGE:		20100310
EFFECTIVENESS DATE:		20100311

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			DRIEHAUS INSTITUTIONAL SMALL CAP LP
		CENTRAL INDEX KEY:			0001094178
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		D/A
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	021-82961
		FILM NUMBER:		10672073

	BUSINESS ADDRESS:	
		STREET 1:		DRIEHAUS CAPITAL MANAGEMENT (USVI) LLC
		STREET 2:		25 EAST ERIE STREET
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60611-2703
		BUSINESS PHONE:		312-587-3800

	MAIL ADDRESS:	
		STREET 1:		DRIEHAUS CAPITAL MANAGEMENT (USVI) LLC
		STREET 2:		25 EAST ERIE STREET
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60611-2703
</SEC-HEADER>
<DOCUMENT>
<TYPE>D/A
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<edgarSubmission>

    <schemaVersion>X0603</schemaVersion>

    <submissionType>D/A</submissionType>

    <testOrLive>LIVE</testOrLive>

    <primaryIssuer>
        <cik>0001094178</cik>
        <entityName>DRIEHAUS INSTITUTIONAL SMALL CAP LP</entityName>
        <issuerAddress>
            <street1>DRIEHAUS CAPITAL MANAGEMENT (USVI) LLC</street1>
            <street2>25 EAST ERIE STREET</street2>
            <city>CHICAGO</city>
            <stateOrCountry>IL</stateOrCountry>
            <zipCode>60611</zipCode>
        </issuerAddress>
        <issuerPhoneNumber>312-587-3800</issuerPhoneNumber>
        <jurisdictionOfInc>DELAWARE</jurisdictionOfInc>
        <issuerPreviousNameList>
            <previousName>Driehaus Small Cap Growth Fund, L.P.</previousName>
        </issuerPreviousNameList>
        <edgarPreviousNameList>
            <value>None</value>
        </edgarPreviousNameList>
        <entityType>Limited Partnership</entityType>
        <yearOfInc>
            <overFiveYears>true</overFiveYears>
        </yearOfInc>
    </primaryIssuer>

    <relatedPersonsList>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>n/a</firstName>
                <lastName>Driehaus Capital Management (USVI) LLC</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>25 East Erie Street</street1>
                <city>Chicago</city>
                <stateOrCountry>IL</stateOrCountry>
                <zipCode>60611</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>General Partner</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>n/a</firstName>
                <lastName>Driehaus Capital Management LLC</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>25 East Erie Street</street1>
                <city>Chicago</city>
                <stateOrCountry>IL</stateOrCountry>
                <zipCode>60611</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Investment Adviser</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Richard</firstName>
                <middleName>H.</middleName>
                <lastName>Driehaus</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Driehaus Capital Management (USVI) LLC</street1>
                <street2>25 East Erie Street</street2>
                <city>Chicago</city>
                <stateOrCountry>IL</stateOrCountry>
                <zipCode>60611</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Robert</firstName>
                <lastName>Gordon</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Driehaus Capital Management (USVI) LLC</street1>
                <street2>25 East Erie Street</street2>
                <city>Chicago</city>
                <stateOrCountry>IL</stateOrCountry>
                <zipCode>60611</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Heather</firstName>
                <middleName>S.</middleName>
                <lastName>Paterson</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Driehaus Capital Management (USVI) LLC</street1>
                <street2>25 East Erie Street</street2>
                <city>Chicago</city>
                <stateOrCountry>IL</stateOrCountry>
                <zipCode>60611</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Mary</firstName>
                <middleName>H.</middleName>
                <lastName>Weiss</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Driehaus Capital Management (USVI) LLC</street1>
                <street2>25 East Erie Street</street2>
                <city>Chicago</city>
                <stateOrCountry>IL</stateOrCountry>
                <zipCode>60611</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Michelle</firstName>
                <middleName>L.</middleName>
                <lastName>Cahoon</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Driehaus Capital Management (USVI) LLC</street1>
                <street2>25 East Erie Street</street2>
                <city>Chicago</city>
                <stateOrCountry>IL</stateOrCountry>
                <zipCode>60611</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
    </relatedPersonsList>

    <offeringData>
        <industryGroup>
            <industryGroupType>Pooled Investment Fund</industryGroupType>
            <investmentFundInfo>
                <investmentFundType>Hedge Fund</investmentFundType>
                <is40Act>false</is40Act>
            </investmentFundInfo>
        </industryGroup>
        <issuerSize>
            <aggregateNetAssetValueRange>Decline to Disclose</aggregateNetAssetValueRange>
        </issuerSize>
        <federalExemptionsExclusions>
            <item>06</item>
            <item>3C</item>
            <item>3C.7</item>
        </federalExemptionsExclusions>
        <typeOfFiling>
            <newOrAmendment>
                <isAmendment>true</isAmendment>
                <previousAccessionNumber>0001300724-09-000010</previousAccessionNumber>
            </newOrAmendment>
            <dateOfFirstSale>
                <value>1999-08-02</value>
            </dateOfFirstSale>
        </typeOfFiling>
        <durationOfOffering>
            <moreThanOneYear>true</moreThanOneYear>
        </durationOfOffering>
        <typesOfSecuritiesOffered>
            <isPooledInvestmentFundType>true</isPooledInvestmentFundType>
        </typesOfSecuritiesOffered>
        <businessCombinationTransaction>
            <isBusinessCombinationTransaction>false</isBusinessCombinationTransaction>
            <clarificationOfResponse></clarificationOfResponse>
        </businessCombinationTransaction>
        <minimumInvestmentAccepted>500000</minimumInvestmentAccepted>
        <salesCompensationList>
            <recipient>
                <recipientName>Driehaus Securities LLC</recipientName>
                <recipientCRDNumber>8197</recipientCRDNumber>
                <associatedBDName>None</associatedBDName>
                <associatedBDCRDNumber>None</associatedBDCRDNumber>
                <recipientAddress>
                    <street1>25 East Erie Street</street1>
                    <city>Chicago</city>
                    <stateOrCountry>IL</stateOrCountry>
                    <zipCode>60611</zipCode>
                </recipientAddress>
                <statesOfSolicitationList>
                    <value>All States</value>
                </statesOfSolicitationList>
            </recipient>
        </salesCompensationList>
        <offeringSalesAmounts>
            <totalOfferingAmount>Indefinite</totalOfferingAmount>
            <totalAmountSold>49864308</totalAmountSold>
            <totalRemaining>Indefinite</totalRemaining>
            <clarificationOfResponse></clarificationOfResponse>
        </offeringSalesAmounts>
        <investors>
            <hasNonAccreditedInvestors>true</hasNonAccreditedInvestors>
            <numberNonAccreditedInvestors>1</numberNonAccreditedInvestors>
            <totalNumberAlreadyInvested>31</totalNumberAlreadyInvested>
        </investors>
        <salesCommissionsFindersFees>
            <salesCommissions>
                <dollarAmount>387</dollarAmount>
                <isEstimate>true</isEstimate>
            </salesCommissions>
            <findersFees>
                <dollarAmount>0</dollarAmount>
            </findersFees>
            <clarificationOfResponse>The Investment Adviser pays up to 20% of its advisory fee to the selling agents - see item 12.  The current offering commenced prior to 3/15/09; item 15 reflects the requested information commencing from such date.</clarificationOfResponse>
        </salesCommissionsFindersFees>
        <useOfProceeds>
            <grossProceedsUsed>
                <dollarAmount>0</dollarAmount>
            </grossProceedsUsed>
            <clarificationOfResponse></clarificationOfResponse>
        </useOfProceeds>
        <signatureBlock>
            <authorizedRepresentative>false</authorizedRepresentative>
            <signature>
                <issuerName>DRIEHAUS INSTITUTIONAL SMALL CAP LP</issuerName>
                <signatureName>Heather S. Paterson</signatureName>
                <nameOfSigner>Heather S. Paterson</nameOfSigner>
                <signatureTitle>Assistant Secretary of the General Partner</signatureTitle>
                <signatureDate>2010-03-10</signatureDate>
            </signature>
        </signatureBlock>
    </offeringData>
</edgarSubmission>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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