-----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,
 LiDR8OjW6CYOhqdb/zqe4c8PqSN/WKj4FoIdlhRknn3quQV5zgrw5IbbcokfNT6l
 eMn3LXjPw4MIr9vCBQG8pg==

<SEC-DOCUMENT>0001407856-10-000001.txt : 20100310
<SEC-HEADER>0001407856-10-000001.hdr.sgml : 20100310
<ACCEPTANCE-DATETIME>20100309180910
ACCESSION NUMBER:		0001407856-10-000001
CONFORMED SUBMISSION TYPE:	D/A
PUBLIC DOCUMENT COUNT:		1
ITEM INFORMATION:		Rule 506
FILED AS OF DATE:		20100310
DATE AS OF CHANGE:		20100309
EFFECTIVENESS DATE:		20100310

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Morgan Stanley Smith Barney Mark J. Walsh & Co L.P.
		CENTRAL INDEX KEY:			0001229138
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		D/A
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	021-54765
		FILM NUMBER:		10668253

	BUSINESS ADDRESS:	
		STREET 1:		522 FIFTH AVENUE
		STREET 2:		13TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10036
		BUSINESS PHONE:		212-296-1999

	MAIL ADDRESS:	
		STREET 1:		522 FIFTH AVENUE
		STREET 2:		13TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10036

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MORGAN STANLEY MARK J WALSH & CO LP
		DATE OF NAME CHANGE:	20030425
</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>0001229138</cik>
        <entityName>Morgan Stanley Smith Barney Mark J. Walsh &amp; Co L.P.</entityName>
        <issuerAddress>
            <street1>522 FIFTH AVENUE</street1>
            <street2>13TH FLOOR</street2>
            <city>NEW YORK</city>
            <stateOrCountry>NY</stateOrCountry>
            <zipCode>10036</zipCode>
        </issuerAddress>
        <issuerPhoneNumber>212-296-1999</issuerPhoneNumber>
        <jurisdictionOfInc>DELAWARE</jurisdictionOfInc>
        <edgarPreviousNameList>
            <previousName>MORGAN STANLEY MARK J WALSH &amp; CO LP</previousName>
        </edgarPreviousNameList>
        <entityType>Limited Partnership</entityType>
        <yearOfInc>
            <overFiveYears>true</overFiveYears>
        </yearOfInc>
    </primaryIssuer>

    <relatedPersonsList>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>n/a</firstName>
                <lastName>Demeter Management LLC</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>522 Fifth Avenue</street1>
                <street2>13th Floor</street2>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <zipCode>10036</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>General Partner</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Jacques</firstName>
                <lastName>Chappuis</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>c/o Demeter Management LLC</street1>
                <street2>522 Fifth Avenue, 13th Floor</street2>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <zipCode>10036</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Walter</firstName>
                <lastName>Davis</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>c/o Demeter Management LLC</street1>
                <street2>522 Fifth Avenue, 13th Floor</street2>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <zipCode>10036</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Harry</firstName>
                <lastName>Handler</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>c/o Demeter Management LLC</street1>
                <street2>522 Fifth Avenue, 13th Floor</street2>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <zipCode>10036</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Douglas</firstName>
                <lastName>Ketterer</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>c/o Demeter Management LLC</street1>
                <street2>522 Fifth Avenue, 13th Floor</street2>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <zipCode>10036</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Michael</firstName>
                <lastName>McGrath</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>c/o Demeter Management LLC</street1>
                <street2>522 Fifth Avenue, 13th Floor</street2>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <zipCode>10036</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Jose</firstName>
                <lastName>Morales</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>c/o Demeter Management LLC</street1>
                <street2>522 Fifth Avenue, 13th Floor</street2>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <zipCode>10036</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Frank</firstName>
                <lastName>Zafran</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>c/o Demeter Management LLC</street1>
                <street2>522 Fifth Avenue, 13th Floor</street2>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <zipCode>10036</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Christian</firstName>
                <lastName>Angstadt</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>c/o Demeter Management LLC</street1>
                <street2>522 Fifth Avenue, 13th Floor</street2>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <zipCode>10036</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Jeremy</firstName>
                <lastName>Beal</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>c/o Demeter Management LLC</street1>
                <street2>522 Fifth Avenue, 13th Floor</street2>
                <city>New York</city>
                <stateOrCountry>NY</stateOrCountry>
                <zipCode>10036</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></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>
        </federalExemptionsExclusions>
        <typeOfFiling>
            <newOrAmendment>
                <isAmendment>true</isAmendment>
                <previousAccessionNumber>0001116282-10-000004</previousAccessionNumber>
            </newOrAmendment>
            <dateOfFirstSale>
                <value>2001-05-01</value>
            </dateOfFirstSale>
        </typeOfFiling>
        <durationOfOffering>
            <moreThanOneYear>true</moreThanOneYear>
        </durationOfOffering>
        <typesOfSecuritiesOffered>
            <isPooledInvestmentFundType>true</isPooledInvestmentFundType>
        </typesOfSecuritiesOffered>
        <businessCombinationTransaction>
            <isBusinessCombinationTransaction>false</isBusinessCombinationTransaction>
            <clarificationOfResponse></clarificationOfResponse>
        </businessCombinationTransaction>
        <minimumInvestmentAccepted>100000</minimumInvestmentAccepted>
        <salesCompensationList>
            <recipient>
                <recipientName>Morgan Stanley &amp; Co. Incorporated</recipientName>
                <recipientCRDNumber>8209</recipientCRDNumber>
                <associatedBDName>None</associatedBDName>
                <associatedBDCRDNumber>None</associatedBDCRDNumber>
                <recipientAddress>
                    <street1>1585 Broadway</street1>
                    <city>New York</city>
                    <stateOrCountry>NY</stateOrCountry>
                    <zipCode>10036</zipCode>
                </recipientAddress>
                <statesOfSolicitationList>
                    <value>All States</value>
                </statesOfSolicitationList>
            </recipient>
        </salesCompensationList>
        <offeringSalesAmounts>
            <totalOfferingAmount>Indefinite</totalOfferingAmount>
            <totalAmountSold>34284654</totalAmountSold>
            <totalRemaining>Indefinite</totalRemaining>
            <clarificationOfResponse></clarificationOfResponse>
        </offeringSalesAmounts>
        <investors>
            <hasNonAccreditedInvestors>false</hasNonAccreditedInvestors>
            <totalNumberAlreadyInvested>190</totalNumberAlreadyInvested>
        </investors>
        <salesCommissionsFindersFees>
            <salesCommissions>
                <dollarAmount>68000</dollarAmount>
                <isEstimate>true</isEstimate>
            </salesCommissions>
            <findersFees>
                <dollarAmount>0</dollarAmount>
            </findersFees>
            <clarificationOfResponse>Issuer does not pay upfront sales commissions. Up to 42% of brokerage fees are paid to the selling agents on an ongoing basis. Current offering began prior to 3/15/2009; item 15 reflects requested info commencing from 3/1/2009.</clarificationOfResponse>
        </salesCommissionsFindersFees>
        <useOfProceeds>
            <grossProceedsUsed>
                <dollarAmount>0</dollarAmount>
            </grossProceedsUsed>
            <clarificationOfResponse></clarificationOfResponse>
        </useOfProceeds>
        <signatureBlock>
            <authorizedRepresentative>false</authorizedRepresentative>
            <signature>
                <issuerName>Morgan Stanley Smith Barney Mark J. Walsh &amp; Co L.P.</issuerName>
                <signatureName>Jeremy Beal</signatureName>
                <nameOfSigner>Jeremy Beal</nameOfSigner>
                <signatureTitle>Authorized Signatory of the General Partner</signatureTitle>
                <signatureDate>2010-03-09</signatureDate>
            </signature>
        </signatureBlock>
    </offeringData>
</edgarSubmission>
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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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