-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 CkDxNNYFdQ7Pwd1RnQRbktZ3tFTMTlQ01nYfwkuPBDMtqEKQEGy3TtStbrWmOgIv
 /rZHmT2w0htp4a+fYRZygg==

<SEC-DOCUMENT>0001140361-10-025680.txt : 20100616
<SEC-HEADER>0001140361-10-025680.hdr.sgml : 20100616
<ACCEPTANCE-DATETIME>20100616154517
ACCESSION NUMBER:		0001140361-10-025680
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100615
FILED AS OF DATE:		20100616
DATE AS OF CHANGE:		20100616

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			HAMADA ROBERT S
		CENTRAL INDEX KEY:			0001179608

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05415
		FILM NUMBER:		10900621

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>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-06-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001179608</rptOwnerCik>
            <rptOwnerName>HAMADA ROBERT S</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>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>2010-06-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>14.13</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>17455</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The transaction was executed in multiple trades at prices ranging from $14.09 to $14.17.  The price reported above reflects the weighted average sale price.  The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Robert J. Perna, Attorney-in-Fact</signatureName>
        <signatureDate>2010-06-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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