Aspen Technology Changes Date of Earnings Release to September 13, 2005

August 29, 2005

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Aug. 29, 2005--Aspen Technology, Inc. (Nasdaq: AZPN), the leading provider of software and services to the process industries, today announced it has changed the date it plans to release its financial results for its fourth quarter of fiscal 2005, ended June 30, 2005. The Company had previously announced that it intended to issue its quarterly and fiscal year earnings on August 30, 2005. AspenTech now anticipates it will report its fourth quarter results concurrently with the filing of its Form 10-K on September 13, 2005 at 5:00 p.m. EST in order to allow additional time for the Company and its auditors to complete the year-end audit.

About AspenTech

Aspen Technology, Inc. provides industry-leading software and professional services that help process companies improve efficiency and profitability by enabling them to model, manage and control their operations. The new generation of integrated aspenONE(TM) solutions are aligned with the key industry business processes, providing manufacturers the capabilities they need to optimize operational performance, make real-time decisions and synchronize the plant and supply chain. Over 1,500 leading companies already rely on AspenTech's software, including Aventis, Bayer, BASF, BP, ChevronTexaco, DuPont, ExxonMobil, Fluor, GlaxoSmithKline, Shell, and Total. For more information, visit

This press release contains forward-looking statements for purposes of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Actual results may vary significantly from AspenTech's expectations based on a number of risks and uncertainties, including, without limitation: AspenTech's plan to improve operational performance may not be implemented effectively; AspenTech has identified material weaknesses in its internal controls with respect to software license revenue recognition and other matters, that, if not remedied effectively, could result in material misstatements; AspenTech's lengthy sales cycle makes it difficult to predict quarterly operating results; fluctuations in AspenTech's quarterly operating results; AspenTech's dependence on customers in the cyclical chemicals, petrochemicals and petroleum industries; AspenTech's ability to raise additional capital as required; intense competition; AspenTech's need to develop and market products successfully; reliance on relationships with strategic partners; and other risk factors described from time to time in AspenTech's periodic reports filed with the Securities and Exchange Commission. AspenTech cannot guarantee any future results, levels of activity, performance, or achievements. AspenTech expressly disclaims any current intention to update forward-looking statements after the date of this press release.

Aspen Technology, Inc.
Joshua Young, 617-949-1274
Director of Investor Relations & Corp. Communications