-----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,
 UebHCcSxVtnPD0r5PeTuXtC6v/J/avbXlY3d1+VWyNseU9gHoRJQbjSlpvVEMxlI
 arPXLu04OoPctRPz+1Qqww==

<SEC-DOCUMENT>0001179110-04-016736.txt : 20040818
<SEC-HEADER>0001179110-04-016736.hdr.sgml : 20040818
<ACCEPTANCE-DATETIME>20040818145627
ACCESSION NUMBER:		0001179110-04-016736
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040817
FILED AS OF DATE:		20040818

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TCW CONVERTIBLE SECURITIES FUND INC
		CENTRAL INDEX KEY:			0000809559
		IRS NUMBER:				930939398
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		865 S FIGUEROA ST STE 1800
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90071
		BUSINESS PHONE:		2132440000

	MAIL ADDRESS:	
		STREET 1:		865 S. FIGUEROA STREET,
		STREET 2:		SUITE 1800
		CITY:			LOSANGELES
		STATE:			CA
		ZIP:			90017

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LYON THOMAS D
		CENTRAL INDEX KEY:			0001118968

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-04980
		FILM NUMBER:		04984018

	BUSINESS ADDRESS:	
		STREET 1:		865 S. FIGUEROA STREET
		STREET 2:		SUITE 1800
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90017
		BUSINESS PHONE:		2132440073

	MAIL ADDRESS:	
		STREET 1:		865 S. FIGUEROA STREET
		STREET 2:		SUITE 1800
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90017
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-08-17</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000809559</issuerCik>
        <issuerName>TCW CONVERTIBLE SECURITIES FUND INC</issuerName>
        <issuerTradingSymbol>CVT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001118968</rptOwnerCik>
            <rptOwnerName>LYON THOMAS D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TCW CONVERTIBLE SECURITIES FUND, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>865 S. FIGUEROA ST., STE. 1800</rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior V.P.</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-08-17</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4600</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.66</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>23075</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Purchased 2,300 shares each for Kathryn E. Lyon and James D. Lyon (Minor Children)</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Harold H. Henderson for Thomas D. Lyon by Power of Attorney dated August 20, 2002</signatureName>
        <signatureDate>2004-08-18</signatureDate>
    </ownerSignature>
</ownershipDocument>

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