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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 WFjK8vJhxOCTcG4AvD080QX90NNHOg2OB3MZ6ydgq62jhx81oCqeeLibPuJQ4TLH
 k5kCvlxua+cjDT4OcTJ/DA==

<SEC-DOCUMENT>0001140361-10-018756.txt : 20100504
<SEC-HEADER>0001140361-10-018756.hdr.sgml : 20100504
<ACCEPTANCE-DATETIME>20100504152125
ACCESSION NUMBER:		0001140361-10-018756
CONFORMED SUBMISSION TYPE:	3/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100422
FILED AS OF DATE:		20100504
DATE AS OF CHANGE:		20100504

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SCHMEDA PATRICIA J
		CENTRAL INDEX KEY:			0001490673

	FILING VALUES:
		FORM TYPE:		3/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05415
		FILM NUMBER:		10796941

	MAIL ADDRESS:	
		STREET 1:		3400 NORTH WOLF ROAD
		CITY:			FRANKLIN PARK
		STATE:			IL
		ZIP:			60131

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CASTLE A M & CO
		CENTRAL INDEX KEY:			0000018172
		STANDARD INDUSTRIAL CLASSIFICATION:	WHOLESALE-METALS SERVICE CENTERS & OFFICES [5051]
		IRS NUMBER:				360879160
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1207

	BUSINESS ADDRESS:	
		STREET 1:		3400 N WOLF RD
		CITY:			FRANKLIN PARK
		STATE:			IL
		ZIP:			60131
		BUSINESS PHONE:		7084557111

	MAIL ADDRESS:	
		STREET 1:		3400 N WOLF RD
		CITY:			FRANKLIN PARK
		STATE:			IL
		ZIP:			60131
</SEC-HEADER>
<DOCUMENT>
<TYPE>3/A
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 3/A
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0203</schemaVersion>

    <documentType>3/A</documentType>

    <periodOfReport>2010-04-22</periodOfReport>

    <dateOfOriginalSubmission>2010-05-03</dateOfOriginalSubmission>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000018172</issuerCik>
        <issuerName>CASTLE A M &amp; CO</issuerName>
        <issuerTradingSymbol>CAS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001490673</rptOwnerCik>
            <rptOwnerName>SCHMEDA PATRICIA J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3400 NORTH WOLF ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>FRANKLIN PARK</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60131</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP, Information Technology</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5247.98</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">This amendment is being made to report 1,547.98 shares of common stock owned directly by the reporting person that were omitted from the reporting person's original Form 3.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Robert J. Perna, Attorney-in-Fact</signatureName>
        <signatureDate>2010-05-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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