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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0001179110-07-019204.txt : 20071002
<SEC-HEADER>0001179110-07-019204.hdr.sgml : 20071002
<ACCEPTANCE-DATETIME>20071002171555
ACCESSION NUMBER:		0001179110-07-019204
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070630
FILED AS OF DATE:		20071002
DATE AS OF CHANGE:		20071002

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			JOHNSON JOEL W
		CENTRAL INDEX KEY:			0001190003

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09328
		FILM NUMBER:		071150821

	BUSINESS ADDRESS:	
		STREET 1:		1 HORMEL PLACE
		CITY:			AUSTIN
		STATE:			MN
		ZIP:			55912

	MAIL ADDRESS:	
		STREET 1:		1 HORMEL PLACE
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			55912

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ECOLAB INC
		CENTRAL INDEX KEY:			0000031462
		STANDARD INDUSTRIAL CLASSIFICATION:	SOAP, DETERGENT, CLEANING PREPARATIONS, PERFUMES, COSMETICS [2840]
		IRS NUMBER:				410231510
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ECOLAB CORPORATE CENTER
		STREET 2:		370 WABASHA STREET NORTH
		CITY:			ST PAUL
		STATE:			MN
		ZIP:			55102
		BUSINESS PHONE:		6512932233

	MAIL ADDRESS:	
		STREET 1:		ECOLAB CORPORATE CENTER
		STREET 2:		370 WABASHA STREET NORTH
		CITY:			ST. PAUL
		STATE:			MN
		ZIP:			55102

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ECONOMICS LABORATORY INC
		DATE OF NAME CHANGE:	19861203
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4/A -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2007-06-30</periodOfReport>

    <dateOfOriginalSubmission>2007-07-03</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000031462</issuerCik>
        <issuerName>ECOLAB INC</issuerName>
        <issuerTradingSymbol>ECL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001190003</rptOwnerCik>
            <rptOwnerName>JOHNSON JOEL W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>THE HORMEL FOUNDATION</rptOwnerStreet1>
            <rptOwnerStreet2>301 N. MAIN STREET</rptOwnerStreet2>
            <rptOwnerCity>AUSTIN</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55912</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-06-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>413.08</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>42.97</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>60514.96</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Includes 64.29 shares acquired pursuant to a dividend reinvestment feature of the Ecolab Inc. 2001 Non-Employee Director Stock Option and Deferred Compensation Plan.</footnote>
        <footnote id="F2">This amended Form 4 is being filed to decrease by 46.68 shares the end of period holdings from Table I of the reporting person's original Form 4 filed on July 3, 2007.  These 46.68 shares, which were acquired by dividend reinvestment under the Dividend Reinvestment Plan for shareholders of Ecolab sponsored by Computershare Turst Company, Inc., were previously reported by the reporting person on a Form 4 filed on May 8, 2007.  As of June 30, 2007, the reporting person owned 60,514.96 shares of Common Stock.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ David F. Duvick, Attorney-in-Fact for Joel W. Johnson</signatureName>
        <signatureDate>2007-10-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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