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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,
 N0IWC3IlX8EaL268zi76srvdgUALrPsK1dMzo5k6VlpNC4B3ioyRyLG1J6cxIe/s
 j6fKGWuBcChghsNCzuHtqQ==

<SEC-DOCUMENT>0001209191-03-017647.txt : 20030818
<SEC-HEADER>0001209191-03-017647.hdr.sgml : 20030818
<ACCEPTANCE-DATETIME>20030818163352
ACCESSION NUMBER:		0001209191-03-017647
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030814
FILED AS OF DATE:		20030818

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			KINGSLEY DOUGLAS A
		CENTRAL INDEX KEY:			0001197537

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-24786
		FILM NUMBER:		03853467

	MAIL ADDRESS:	
		STREET 1:		C/O ADVENT INTERNATIONAL CORP
		STREET 2:		75 STATE ST 29TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02104

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ASPEN TECHNOLOGY INC /DE/
		CENTRAL INDEX KEY:			0000929940
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMPUTER PROGRAMMING SERVICES [7371]
		IRS NUMBER:				042739697
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		TEN CANAL PARK
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141
		BUSINESS PHONE:		6179491000

	MAIL ADDRESS:	
		STREET 1:		TEN CANAL PARK
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>b47504dz.xml
<DESCRIPTION>MAIN DOCUMENT DESCRIPTION
<TEXT>
<XML>
<?xml version="1.0"?><ownershipDocument><schemaVersion>X0201</schemaVersion>    <documentType>3</documentType><periodOfReport>2003-08-14</periodOfReport><noSecuritiesOwned>0</noSecuritiesOwned><issuer><issuerCik>0000929940</issuerCik><issuerName>ASPEN TECHNOLOGY INC /DE/</issuerName>        <issuerTradingSymbol>AZPN</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001197537</rptOwnerCik><rptOwnerName>KINGSLEY DOUGLAS A</rptOwnerName></reportingOwnerId><reportingOwnerAddress><rptOwnerStreet1>C/O ADVENT INTERNATIONAL CORPORATION</rptOwnerStreet1><rptOwnerStreet2>75 STATE STREET, 29TH FLOOR</rptOwnerStreet2><rptOwnerCity>BOSTON</rptOwnerCity><rptOwnerState>MA</rptOwnerState><rptOwnerZipCode>02109</rptOwnerZipCode><rptOwnerStateDescription></rptOwnerStateDescription></reportingOwnerAddress><reportingOwnerRelationship><isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><derivativeTa
ble><derivativeHolding><securityTitle><value>Series D-1 Convertible Preferred Stock</value><footnoteId id="F1" /></securityTitle><conversionOrExercisePrice><value>0</value><footnoteId id="F2" /></conversionOrExercisePrice><exerciseDate><value>2003-08-14</value></exerciseDate><expirationDate><value>1988-08-08</value><footnoteId id="F3" /></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>common stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>44000.</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See footnote 4.</value><footnoteId id="F4" /></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Warrants to purchase common stock</value></securityTitle><conversionOrExercisePrice><value>3.33</value></conversionOrExercisePrice><exerciseDate><value>2003-08-14</value></exerciseDate><expirationDate><value>2010-08-
14</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>common stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>8790.</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See footnote 4.</value><footnoteId id="F4" /></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">Each of the series D-1 shares is convertible into a number of shares of common stock equal to its stated value of $333.00 per share (subject to adjustment) divided by the conversion price of $3.33 per share (subject to adjustment).</footnote><footnote id="F2">Each of the series D-1 shares is convertible into a number of shares of common stock equal to its stated value of $333.00 per share (subject to adjustment) divided by the conversion price of $3.33 per share (subject to adjustment).</footnote><footnote id="F3">Shares may be conver
ted into common stock on a perpetual basis.</footnote><footnote id="F4">Shares are indirectly beneficially owned as a limited partner of Advent Partners II, Advent Partners DMC-III, Advent Partners GPE-III &amp; Advent Partners(NA)GPE-III Limited Partnerships.</footnote></footnotes><ownerSignature><signatureName>/s/ Janet L. Hennessy, Attorney-in-Fact</signatureName><signatureDate>2003-08-14</signatureDate></ownerSignature></ownershipDocument>

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</TEXT>
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</SEC-DOCUMENT>
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