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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 NjAALNQUz9E9AENRzl+1sCmHGCFzOPa+FM4LufuDs2R/atPwt6Nn9CGW4C5q96Gr
 VtsJcuJ8sXv3IqKdMHEwog==

<SEC-DOCUMENT>0001015402-03-003022.txt : 20030801
<SEC-HEADER>0001015402-03-003022.hdr.sgml : 20030801
<ACCEPTANCE-DATETIME>20030801122234
ACCESSION NUMBER:		0001015402-03-003022
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030730
FILED AS OF DATE:		20030801

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:		03817057

	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>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2003-07-30</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 LN.</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>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>

        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2003-07-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4950</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>20.0462</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>78.728</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Mr. Schwartz also indirectly owns 3,453 shares held in the name of his spouse.</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>Leonard S. Schwartz</signatureName>
        <signatureDate>2003-07-30</signatureDate>
    </ownerSignature>

</ownershipDocument>

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