-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001182338-04-000004.txt : 20040427
<SEC-HEADER>0001182338-04-000004.hdr.sgml : 20040427
<ACCEPTANCE-DATETIME>20040427142725
ACCESSION NUMBER:		0001182338-04-000004
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040423
FILED AS OF DATE:		20040427

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PETERS AULANA L
		CENTRAL INDEX KEY:			0001192904

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-07182
		FILM NUMBER:		04756495

	MAIL ADDRESS:	
		STREET 1:		MERRILL LYNCH CORP
		STREET 2:		222 BROADWAY 17TH FL
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10038

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MERRILL LYNCH & CO INC
		CENTRAL INDEX KEY:			0000065100
		STANDARD INDUSTRIAL CLASSIFICATION:	SECURITY BROKERS, DEALERS & FLOTATION COMPANIES [6211]
		IRS NUMBER:				132740599
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		4 WORLD FINANCIAL CTR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10080
		BUSINESS PHONE:		2124491000

	MAIL ADDRESS:	
		STREET 1:		4 WORLD FINANCIAL CTR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10080
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-04-23</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000065100</issuerCik>
        <issuerName>MERRILL LYNCH &amp; CO INC</issuerName>
        <issuerTradingSymbol>MER</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001192904</rptOwnerCik>
            <rptOwnerName>PETERS AULANA L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MERRILL LYNCH &amp; CO., INC.</rptOwnerStreet1>
            <rptOwnerStreet2>4 WORLD FINANCIAL CENTER</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10080</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-04-23</value>
                <footnoteId id="F1"/>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1275</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8011</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5691</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Trust</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option - Right to Acquire</value>
                <footnoteId id="F4"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>56.88</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-04-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3824</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2014-04-23</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3824</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3824</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">These Deferred Stock Units were granted on April 23, 2004 pursuant to the Merrill Lynch &amp; Co., Inc. Deferred Stock Unit and Stock Option Plan for Non-Employee Directors, as amended (the &quot;Plan&quot;).  Deferred Stock Units are payable in Merrill Lynch &amp; Co., Inc. Common Stock upon the earlier of the fifth Annual Meeting of Stockholders following the date of their grant or the director's End of Service Date, as defined in the Plan.  Transactions under the Plan are exempt under Rule 16b-3.</footnote>
        <footnote id="F2">This total reflects the reinvestment of dividend equivalents into Deferred Units and Deferred Stock Units pursuant to the terms of the Merrill Lynch &amp; Co., Inc. Deferred Stock Unit and Stock Option Plan for Non-Employee Directors, as amended; these transactions are exempt from reporting pursuant to Rule 16a-3 and/or 16a-11.</footnote>
        <footnote id="F3">These shares are being held in the Peters Family Trust, a living trust for which the reporting person and the spouse of the reporting person are trustees and beneficiaries.</footnote>
        <footnote id="F4">These stock options were granted under the Merrill Lynch &amp; Co., Inc. Deferred Stock Unit and Stock Option Plan for Non-Employee Directors, as amended.  Transactions under this Plan are exempt under Rule 16b-3.</footnote>
        <footnote id="F5">All stock options will become exercisable after 10/31/04.</footnote>
    </footnotes>

    <remarks>All reported positions have been rounded down to the nearest whole number.</remarks>

    <ownerSignature>
        <signatureName>Aulana L. Peters                            (by Michael A. LaMaina, as agent)</signatureName>
        <signatureDate>2004-04-27</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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