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

    <schemaVersion>X0704</schemaVersion>

    <submissionType>D/A</submissionType>

    <testOrLive>LIVE</testOrLive>

    <primaryIssuer>
        <cik>0001408861</cik>
        <entityName>ACADIAN ALL COUNTRY WORLD EX US LONG-SHORT FUND</entityName>
        <issuerAddress>
            <street1>OLD MUTUAL ASSET MANAGEMENT TRUST CO</street1>
            <street2>200 CLARENDON STREET, 52ND FLOOR</street2>
            <city>BOSTON</city>
            <stateOrCountry>MA</stateOrCountry>
            <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
            <zipCode>02116</zipCode>
        </issuerAddress>
        <issuerPhoneNumber>617-369-7300</issuerPhoneNumber>
        <jurisdictionOfInc>DELAWARE</jurisdictionOfInc>
        <issuerPreviousNameList>
            <value>None</value>
        </issuerPreviousNameList>
        <edgarPreviousNameList>
            <value>None</value>
        </edgarPreviousNameList>
        <entityType>Limited Liability Company</entityType>
        <yearOfInc>
            <overFiveYears>true</overFiveYears>
        </yearOfInc>
    </primaryIssuer>

    <relatedPersonsList>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>n/a</firstName>
                <lastName>Old Mutual Asset Management Trust Co</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>200 Clarendon Street, 52nd Floor</street1>
                <city>Boston</city>
                <stateOrCountry>MA</stateOrCountry>
                <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
                <zipCode>02116</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Promoter</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Old Mutual Asset Management Trust Company (&quot;OMAMTC&quot;) is the Managing Member of the Issuer (its portfolio)</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Vincent</firstName>
                <lastName>Manning</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Old Mutual Asset Management Trust Co</street1>
                <street2>200 Clarendon Street, 52nd Floor</street2>
                <city>Boston</city>
                <stateOrCountry>MA</stateOrCountry>
                <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
                <zipCode>02116</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Officer of OMAMTC</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Virginia</firstName>
                <middleName>M.</middleName>
                <lastName>Turner</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Old Mutual Asset Management Trust Co</street1>
                <street2>200 Clarendon Street, 52nd Floor</street2>
                <city>Boston</city>
                <stateOrCountry>MA</stateOrCountry>
                <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
                <zipCode>02116</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Officer of OMAMTC</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Brian</firstName>
                <lastName>Dillon</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Old Mutual Asset Management Trust Co</street1>
                <street2>200 Clarendon Street, 52nd Floor</street2>
                <city>Boston</city>
                <stateOrCountry>MA</stateOrCountry>
                <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
                <zipCode>02116</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Officer of OMAMTC</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Joan</firstName>
                <middleName>R.</middleName>
                <lastName>Gulinello</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Old Mutual Asset Management Trust Co</street1>
                <street2>200 Clarendon Street, 52nd Floor</street2>
                <city>Boston</city>
                <stateOrCountry>MA</stateOrCountry>
                <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
                <zipCode>02116</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Officer of OMAMTC</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Ruth</firstName>
                <middleName>E.</middleName>
                <lastName>Paul</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Old Mutual Asset Management Trust Co</street1>
                <street2>200 Clarendon Street, 52nd Floor</street2>
                <city>Boston</city>
                <stateOrCountry>MA</stateOrCountry>
                <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
                <zipCode>02116</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Officer of OMAMTC</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Linda</firstName>
                <middleName>T.</middleName>
                <lastName>Gibson</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Old Mutual Asset Management Trust Co</street1>
                <street2>200 Clarendon Street, 52nd Floor</street2>
                <city>Boston</city>
                <stateOrCountry>MA</stateOrCountry>
                <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
                <zipCode>02116</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Director of OMAMTC</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Robert</firstName>
                <lastName>Patterson</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Old Mutual Asset Management Trust Co</street1>
                <street2>200 Clarendon Street, 52nd Floor</street2>
                <city>Boston</city>
                <stateOrCountry>MA</stateOrCountry>
                <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
                <zipCode>02116</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Director of OMAMTC</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Karen</firstName>
                <middleName>F.</middleName>
                <lastName>Kupferberg</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Old Mutual Asset Management Trust Co</street1>
                <street2>200 Clarendon Street, 52nd Floor</street2>
                <city>Boston</city>
                <stateOrCountry>MA</stateOrCountry>
                <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
                <zipCode>02116</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Director of OMAMTC</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Peter</firstName>
                <middleName>L.</middleName>
                <lastName>Rollins</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Old Mutual Asset Management Trust Co</street1>
                <street2>200 Clarendon Street, 52nd Floor</street2>
                <city>Boston</city>
                <stateOrCountry>MA</stateOrCountry>
                <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
                <zipCode>02116</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Director of OMAMTC</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Stephen</firstName>
                <middleName>T.</middleName>
                <lastName>Scott</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Old Mutual Asset Management Trust Co</street1>
                <street2>200 Clarendon Street, 52nd Floor</street2>
                <city>Boston</city>
                <stateOrCountry>MA</stateOrCountry>
                <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
                <zipCode>02116</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Director of OMAMTC</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>David</firstName>
                <middleName>H.</middleName>
                <lastName>Smith</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Old Mutual Asset Management Trust Co</street1>
                <street2>200 Clarendon Street, 52nd Floor</street2>
                <city>Boston</city>
                <stateOrCountry>MA</stateOrCountry>
                <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
                <zipCode>02116</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Director of OMAMTC</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Robert</firstName>
                <middleName>D.</middleName>
                <lastName>McDorman, Jr.</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>Old Mutual Asset Management Trust Co</street1>
                <street2>200 Clarendon Street, 52nd Floor</street2>
                <city>Boston</city>
                <stateOrCountry>MA</stateOrCountry>
                <stateOrCountryDescription>MASSACHUSETTS</stateOrCountryDescription>
                <zipCode>02116</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Director of OMAMTC</relationshipClarification>
        </relatedPersonInfo>
    </relatedPersonsList>

    <offeringData>
        <industryGroup>
            <industryGroupType>Pooled Investment Fund</industryGroupType>
            <investmentFundInfo>
                <investmentFundType>Other Investment Fund</investmentFundType>
                <is40Act>false</is40Act>
            </investmentFundInfo>
        </industryGroup>
        <issuerSize>
            <aggregateNetAssetValueRange>Decline to Disclose</aggregateNetAssetValueRange>
        </issuerSize>
        <federalExemptionsExclusions>
            <item>06</item>
            <item>3C.7</item>
        </federalExemptionsExclusions>
        <typeOfFiling>
            <newOrAmendment>
                <isAmendment>true</isAmendment>
                <previousAccessionNumber>0001140361-11-011384</previousAccessionNumber>
            </newOrAmendment>
            <dateOfFirstSale>
                <value>2005-04-01</value>
            </dateOfFirstSale>
        </typeOfFiling>
        <durationOfOffering>
            <moreThanOneYear>true</moreThanOneYear>
        </durationOfOffering>
        <typesOfSecuritiesOffered>
            <isPooledInvestmentFundType>true</isPooledInvestmentFundType>
            <isOtherType>true</isOtherType>
            <descriptionOfOtherType>Commingled investment trust interests</descriptionOfOtherType>
        </typesOfSecuritiesOffered>
        <businessCombinationTransaction>
            <isBusinessCombinationTransaction>false</isBusinessCombinationTransaction>
        </businessCombinationTransaction>
        <minimumInvestmentAccepted>1000000</minimumInvestmentAccepted>
        <salesCompensationList></salesCompensationList>
        <offeringSalesAmounts>
            <totalOfferingAmount>Indefinite</totalOfferingAmount>
            <totalAmountSold>556917992</totalAmountSold>
            <totalRemaining>Indefinite</totalRemaining>
            <clarificationOfResponse>Total aggregate sales amount is $556,917,992.83</clarificationOfResponse>
        </offeringSalesAmounts>
        <investors>
            <hasNonAccreditedInvestors>false</hasNonAccreditedInvestors>
            <totalNumberAlreadyInvested>15</totalNumberAlreadyInvested>
        </investors>
        <salesCommissionsFindersFees>
            <salesCommissions>
                <dollarAmount>0</dollarAmount>
            </salesCommissions>
            <findersFees>
                <dollarAmount>0</dollarAmount>
            </findersFees>
        </salesCommissionsFindersFees>
        <useOfProceeds>
            <grossProceedsUsed>
                <dollarAmount>0</dollarAmount>
            </grossProceedsUsed>
        </useOfProceeds>
        <signatureBlock>
            <authorizedRepresentative>false</authorizedRepresentative>
            <signature>
                <issuerName>ACADIAN ALL COUNTRY WORLD EX US LONG-SHORT FUND</issuerName>
                <signatureName>/s/ Virginia M. Turner</signatureName>
                <nameOfSigner>Virginia M. Turner</nameOfSigner>
                <signatureTitle>Sr Vice President of OMAMTC (on behalf of its portfolio)</signatureTitle>
                <signatureDate>2012-02-23</signatureDate>
            </signature>
        </signatureBlock>
    </offeringData>
</edgarSubmission>
