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Proc-Type: 2001,MIC-CLEAR
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<SEC-DOCUMENT>0000091142-09-000034.txt : 20090601
<SEC-HEADER>0000091142-09-000034.hdr.sgml : 20090601
<ACCEPTANCE-DATETIME>20090601144952
ACCESSION NUMBER:		0000091142-09-000034
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20090601
FILED AS OF DATE:		20090601
DATE AS OF CHANGE:		20090601

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BROUWER WILFRIDUS M
		CENTRAL INDEX KEY:			0001464950

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-00475
		FILM NUMBER:		09864713

	MAIL ADDRESS:	
		STREET 1:		A. O. SMITH (CHINA) INVESTMENT CO., LTD.
		STREET 2:		NO. 49 SOUTH ZHONGSHAN ROAD, 46TH FLOOR
		CITY:			NANJING
		STATE:			F4
		ZIP:			210005

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SMITH A O CORP
		CENTRAL INDEX KEY:			0000091142
		STANDARD INDUSTRIAL CLASSIFICATION:	MOTORS & GENERATORS [3621]
		IRS NUMBER:				390619790
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		P O BOX 245009
		CITY:			MILWAUKEE
		STATE:			WI
		ZIP:			53224-9509
		BUSINESS PHONE:		4143594000

	MAIL ADDRESS:	
		STREET 1:		P O BOX 245009
		CITY:			MILWAUKEE
		STATE:			WI
		ZIP:			53224-9509
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0203</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2009-06-01</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000091142</issuerCik>
        <issuerName>SMITH A O CORP</issuerName>
        <issuerTradingSymbol>AOS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001464950</rptOwnerCik>
            <rptOwnerName>BROUWER WILFRIDUS M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>A. O. SMITH (CHINA) INVESTMENT CO., LTD.</rptOwnerStreet1>
            <rptOwnerStreet2>NO. 49 SOUTH ZHONGSHAN RD., 46TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NANJING</rptOwnerCity>
            <rptOwnerState>F4</rptOwnerState>
            <rptOwnerZipCode>210005</rptOwnerZipCode>
            <rptOwnerStateDescription>CHINA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior V.P., President and GM</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Employee Stock Options (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-03-02</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>10000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Restriced Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6900</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The employee stock options were granted on 03/02/2009 under the A. O. Smith Combined Incentive Compensation Plan, a transaction exempt under Rule 16b-3.  The options become exercisable in three annual installments of 1/3 of the award starting on 03/02/2010.</footnote>
        <footnote id="F2">The restricted stock units were granted on 03/02/2009 under the A. O. Smith Combined Incentive Compensation Plan, a transaction exempt under Rule 16b-3.  The restricted stock units become payable in Common Stock on the vesting date of 03/02/2012.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>James F. Stern, Attorney-in-Fact for Wilfridus M. Brouwer</signatureName>
        <signatureDate>2009-06-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>attach_1.htm
<TEXT>
<HTML><BODY><PRE>POWER OF ATTORNEY

Know all by these presents, that, for good and valuable consideration, the sufficiency and receipt of which are hereby acknowledged, the undersigned hereby constitutes and appoints each of James F. Stern, Kenneth J. Maciolek and Wendy L. Grant, and any of their substitutes, signing singly, the undersigned's true and lawful attorney-in-fact to:

(1) execute for and on behalf of the undersigned (in accordance with Section 16(a) of the Securities Exchange Act of 1934, as amended, and the rules thereunder (the Exchange Act)), in the undersigned's capacity as an officer of A. O. Smith Corporation, a Delaware corporation (the Company), any and all Forms 3, 4 and/or 5, and any amendments thereto, that are necessary or advisable for the undersigned to file under Section 16(a) (collectively, Documents);

(2) do and perform any and all acts for and on behalf of the undersigned that may be necessary or desirable to complete and execute any such Documents and timely file such Documents with the United States Securities and Exchange Commission and any stock exchange or similar authority; and

(3) take any other action of any type whatsoever in connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in such attorney-in-fact's discretion.

The undersigned hereby grants to each such attorney-in-fact full power and authority to do and perform any and every act and thing whatsoever requisite, necessary or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as the undersigned might or could do if personally present, with full power of substitution or revocation, hereby ratifying and confirming all that each such attorney-in-fact (or such attorney-in-fact's substitute or substitutes) shall lawfully do or cause to be done by virtue of this Power of Attorney and the rights and powers herein granted.  The undersigned acknowledges that each attorney-in-fact, in serving in such capacity at the request of the undersigned, is not assuming, nor is such attorney-in-fact's substitute or substitutes or the Company assuming, any of the undersigned's responsibilities to comply with the Exchange Act.  The undersigned agrees to defend and hold harmless each attorney-in-fact (and such attorney-in-f
act's substitute or substitutes) from and against any and all loss, damage or liability that such attorney-in-fact may sustain as a result of any action taken in good faith hereunder.

This Power of Attorney shall remain in full force and effect until the undersigned is no longer required to file Documents with respect to the undersigned's holdings of and transactions in securities issued by the Company, unless earlier revoked by the undersigned in a signed writing delivered to each of the foregoing attorneys-in-fact.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as of this 27th day of May, 2009.





/s/Wilfridus M. Brouwer

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