-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 KVRSPTuZ7+Wa7vV7TID3Ep+fTAYZ7DU1kMUhGnPUKTg067K3aM5PUYkwLMz725Fd
 jSgq8nnkPjimXgL2f7k1Xg==

<SEC-DOCUMENT>0000058492-05-000278.txt : 20050809
<SEC-HEADER>0000058492-05-000278.hdr.sgml : 20050809
<ACCEPTANCE-DATETIME>20050809090259
ACCESSION NUMBER:		0000058492-05-000278
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050805
FILED AS OF DATE:		20050809
DATE AS OF CHANGE:		20050809

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FLANIGAN MATTEW C
		CENTRAL INDEX KEY:			0001229884

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-07845
		FILM NUMBER:		051007644

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		4173588131

	MAIL ADDRESS:	
		STREET 1:		LEGGETT & PLATT INC
		STREET 2:		NO 1 LEGGETT ROAD
		CITY:			CARTHAGE
		STATE:			MO
		ZIP:			64836

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			LEGGETT & PLATT INC
		CENTRAL INDEX KEY:			0000058492
		STANDARD INDUSTRIAL CLASSIFICATION:	HOUSEHOLD FURNITURE [2510]
		IRS NUMBER:				440324630
		STATE OF INCORPORATION:			MO
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		NO. 1 LEGGETT ROAD
		CITY:			CARTHAGE
		STATE:			MO
		ZIP:			64836
		BUSINESS PHONE:		(417) 358-8131

	MAIL ADDRESS:	
		STREET 1:		NO. 1 LEGGETT ROAD
		CITY:			CARTHAGE
		STATE:			MO
		ZIP:			64836
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-08-05</periodOfReport>

    <issuer>
        <issuerCik>0000058492</issuerCik>
        <issuerName>LEGGETT &amp; PLATT INC</issuerName>
        <issuerTradingSymbol>LEG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001229884</rptOwnerCik>
            <rptOwnerName>FLANIGAN MATTEW C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>NO 1 LEGGETT ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CARTHAGE</rptOwnerCity>
            <rptOwnerState>MO</rptOwnerState>
            <rptOwnerZipCode>64836</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior Vice President - CFO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-08-05</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>62.2541</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>21.76</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>12462.9755</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>John A. Lyckman</signatureName>
        <signatureDate>2005-08-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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