ASPEN TECHNOLOGY INC /DE/
EXHIBIT 10.62
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<BR></FONT><FONT SIZE=2><B>Exhibit 10.62    <BR>    </B></FONT></P>

<P ALIGN="CENTER"><FONT SIZE=2><B>[AspenTechnology Letterhead/Logo]  </B></FONT></P>

<P><FONT SIZE=2>August&nbsp;18,
2003 </FONT></P>

<P><FONT SIZE=2>C.
Steven Pringle<BR>
Senior Vice President, M/SC Business Unit </FONT></P>

<P><FONT SIZE=2>Dear
Steve: </FONT></P>

<P><FONT SIZE=2>This
letter amendment references the letter agreement between you and AspenTech dated June&nbsp;24, 2003 (the "Agreement") regarding your FY04 Executive Compensation Plan. Under the terms of the
Agreement, AspenTech agreed that it would grant you an option to purchase the number of shares of AspenTech common stock specified in the Agreement, contingent upon stockholder approval of the Advent
transaction (the "Option"). As you know, the Advent transaction was approved by AspenTech stockholders and closed on August&nbsp;14, 2003. </FONT></P>

<P><FONT SIZE=2>AspenTech
acknowledges that you have voluntarily agreed to reduce the number of shares subject to the Option to which you were entitled in order to make more options available for the general employee
option pool. You hereby confirm, by execution of this letter amendment, that the option granted to you on August&nbsp;18, 2003 for 245,008 shares of AspenTech common stock constitutes full
satisfaction of AspenTech's obligations under the Agreement to grant the Option and that the terms of the Agreement do not entitle you to any additional stock option grants. All other terms of the
Agreement, including those contingent upon the closing of the Advent transaction, remain in full force and effect. </FONT></P>

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<TD WIDTH="32%"><FONT SIZE=2>Best regards,</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="32%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2>&nbsp;</FONT></TD>
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/s/&nbsp;&nbsp;</FONT><FONT SIZE=2>HELEN MOYE</FONT><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="32%"><FONT SIZE=2><BR>
/s/&nbsp;&nbsp;</FONT><FONT SIZE=2>C. STEVEN PRINGLE</FONT><FONT SIZE=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2><BR>&nbsp;</FONT></TD>
<TD WIDTH="32%"><FONT SIZE=2><BR>
Sept.&nbsp;26, 2003</FONT></TD>
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<TD WIDTH="32%"><FONT SIZE=2>Helen Moye</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="32%"><FONT SIZE=2>C. Steven Pringle</FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="32%"><FONT SIZE=2>Date</FONT></TD>
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<TD WIDTH="32%"><FONT SIZE=2><I>Sr. VP Human Resources<BR>
Aspen Technology,&nbsp;Inc.</I></FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="32%"><FONT SIZE=2><I>Senior Vice President, M/SC Business Unit</I></FONT></TD>
<TD WIDTH="3%"><FONT SIZE=2>&nbsp;</FONT></TD>
<TD WIDTH="32%"><FONT SIZE=2>&nbsp;</FONT></TD>
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