-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 5QyNb197u76DpW7GCnAd6g==

<SEC-DOCUMENT>0001140361-03-004265.txt : 20031113
<SEC-HEADER>0001140361-03-004265.hdr.sgml : 20031113
<ACCEPTANCE-DATETIME>20031113111252
ACCESSION NUMBER:		0001140361-03-004265
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031111
FILED AS OF DATE:		20031113

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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SCHWARTZ LEONARD S
		CENTRAL INDEX KEY:			0001200459

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-04217
		FILM NUMBER:		03996335

	BUSINESS ADDRESS:	
		STREET 1:		ONE HOLLOW LN.
		STREET 2:		SUITE 201
		CITY:			LAKE SUCCESS
		STATE:			NY
		ZIP:			10042
		BUSINESS PHONE:		5166276000

	MAIL ADDRESS:	
		STREET 1:		ONE HOLLOW LN.
		STREET 2:		SUITE 201
		CITY:			LAKE SUCCESS
		STATE:			NY
		ZIP:			10042
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>2003-11-11</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000002034</issuerCik>
        <issuerName>ACETO CORP</issuerName>
        <issuerTradingSymbol>ACET</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001200459</rptOwnerCik>
            <rptOwnerName>SCHWARTZ LEONARD S</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>1</isDirector>
<isOfficer>1</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle>Chairman, CEO, President</officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable>
<nonDerivativeTransaction>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<transactionDate>
<value>2003-11-11</value>
</transactionDate>
<deemedExecutionDate>
</deemedExecutionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>S</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>23700</value>
</transactionShares>
<transactionPricePerShare>
<value>17.6489</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode>
<value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>75778</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeTransaction>
<nonDerivativeTransaction>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<transactionDate>
<value>2003-11-12</value>
</transactionDate>
<deemedExecutionDate>
</deemedExecutionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>S</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>10050</value>
</transactionShares>
<transactionPricePerShare>
<value>17.7607</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode>
<value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>65728</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeTransaction>
<nonDerivativeHolding>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>3453</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value>By Spouse</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeHolding>
</nonDerivativeTable>
<remarks></remarks>
<ownerSignature>
<signatureName>Leonard S. Schwartz</signatureName>
<signatureDate>2003-11-13</signatureDate>
</ownerSignature>
</ownershipDocument>

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