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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,
 GBq5gVTLr5m8sqiiyAVhIGRXSdp0gHHDj0/VIip0QZBKBMeZp5XnbieWgbbbYfQE
 VD6bdrgh4SmfKJRSZNYRuw==

<SEC-DOCUMENT>0001140361-04-005246.txt : 20040913
<SEC-HEADER>0001140361-04-005246.hdr.sgml : 20040913
<ACCEPTANCE-DATETIME>20040913161919
ACCESSION NUMBER:		0001140361-04-005246
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040909
FILED AS OF DATE:		20040913
DATE AS OF CHANGE:		20040913

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ROTH DOUGLAS A
		CENTRAL INDEX KEY:			0001203044

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-04217
		FILM NUMBER:		041027733

	MAIL ADDRESS:	
		STREET 1:		9 KIMBERLY DR
		CITY:			E NORTHPORT
		STATE:			NY
		ZIP:			11731

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ACETO CORP
		CENTRAL INDEX KEY:			0000002034
		STANDARD INDUSTRIAL CLASSIFICATION:	WHOLESALE-CHEMICALS & ALLIED PRODUCTS [5160]
		IRS NUMBER:				111720520
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		ONE HOLLOW LANE
		CITY:			LAKE SUCCESS
		STATE:			NY
		ZIP:			11042
		BUSINESS PHONE:		5166276000

	MAIL ADDRESS:	
		STREET 1:		ONE HOLLOW LANE
		CITY:			LAKE SUCCESS
		STATE:			NY
		ZIP:			11042

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ACETO CHEMICAL CO INC
		DATE OF NAME CHANGE:	19851203
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-09-09</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000002034</issuerCik>
        <issuerName>ACETO CORP</issuerName>
        <issuerTradingSymbol>ACET</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001203044</rptOwnerCik>
            <rptOwnerName>ROTH DOUGLAS A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE HOLLOW LANE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 201</rptOwnerStreet2>
            <rptOwnerCity>LAKE SUCCESS</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>11042</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CFO, Secretary, Treasurer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>16.42</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-09-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>20000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2004-09-09</value>
            </exerciseDate>
            <expirationDate>
                <value>2014-09-09</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>20000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>39100</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Douglas A. Roth</signatureName>
        <signatureDate>2004-09-10</signatureDate>
    </ownerSignature>
</ownershipDocument>

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