Aspen Systems, Inc. Ranked Number 135th Fastest Growing Company in North America on Deloitte’s 2006 Technology Fast 500, and 7th on Colorado’s Technology Fast 50.

Wheat Ridge, CO, October 19th – Aspen Systems, Inc. today announced that it ranked Number 135th on Deloitte’s 2006 Technology Fast 500, a ranking of the 500 fastest growing technology, media, telecommunications and life sciences companies in North America. Rankings are based on percentage revenue growth over five years, from 2001-2005. Aspen Systems, Inc. grew 1,426% percent during this period.

“Making Deloitte’s Technology Fast 500 is commendable in today’s highly competitive technology industry,” said Tony Kern, deputy managing principal of Deloitte’s Technology, Media & Telecommunications industry practice. “We congratulate Aspen Systems, Inc. on being on of the 500 fastest growing technology companies in North America.

In addition to ranking on Deloitte’s Technology Fast 500, Aspen Systems, Inc. ranked 7th on Colorado’s Technology Fast 50, which is a ranking of the 50 fastest growing technology firms in Colorado.

Overall, companies that ranked on the 2006 Technology Fast 500 had growth rates ranging from 210 to 48,948 percent over five years, with an average growth rate of 2,147 percent.

Fast 500 Selection and Qualifying Criteria The Fast 500 ranks the fastest growing technology, media, telecommunications and life sciences companies in North America. It is compiled from Deloitte’s 16 regional North American Fast 50 programs, nominations submitted directly to the Fast 500, and public company database research. Companies are selected based on percentage revenue growth from 2001-2005.

Entrants must own proprietary intellectual property or proprietary technology that contributes to a significant portion of the company’s operating revenues or devote a significant proportion of revenues to research and development of technology. Using other companies’ technology or intellectual property in a unique way does not qualify. Base-year operating revenues must be at least $50,000 USD or $75,000 CD, and current-year operating revenues must be at least $5 million USD or CD. Companies must be in business a minimum of five years, and they must be headquartered within North America.

About Aspen Systems, Inc.

Aspen Systems, Inc., a privately held corporation for over 20 years, has been serving the high-performance computing community with expertise in custom clustering solutions, including hardware and software design. Aspen provides a wide variety of high-performance computing disciplines with an emphasis on serving the needs of advanced governmental, educational, and corporate users. Aspen Systems has built their reputation as a leading manufacturer of Beowulf clustering solutions by offering multiple configurations with a choice of processors and connectivity for specific performance needs. First class technical support and state-of-the-art products allow Aspen to create and support systems in the Weather Modeling, Financial Modeling, Chemistry, Physics, Mathematics, Bio-tech, Geophysics Research, and other compute-intensive parallel fields. For more information, visit our website at http://www.aspsys.com

About Deloitte

Deloitte refers to one or more of Deloitte Touche Tohmatsu, a Swiss Verein, its member firms and their respective subsidiaries and affiliates. Deloitte Touche Tohmatsu is an organization of member firms around the world devoted to excellence in providing professional services and advice, focused on client service through a global strategy executed locally in nearly 150 countries. With access to the deep intellectual capital of approximately 135,000 people worldwide, Deloitte delivers services in four professional areas, audit, tax, consulting and financial advisory services, and serves more than one-half of the world’s largest companies, as well as large national enterprises, public institutions, locally important clients, and successful, fast-growing global growth companies. Services are not provided by the Deloitte Touche Tohmatsu Verein and, for regulatory and other reasons, certain member firms do not provide services in all four professional areas.

As a Swiss Verein (association), neither Deloitte Touche Tohmatsu nor any of its member firms has any liability for each other’s acts or omissions. Each of the member firms is a separate and independent legal entity operating under the names “Deloitte”, “Deloitte & Touche”, “Deloitte Touche Tohmatsu” or other related names.

In the United States, Deloitte & Touche USA LLP is the U.S. member firm of Deloitte Touche Tohmatsu and services are provided by the subsidiaries of Deloitte & Touche USA LLP (Deloitte & Touche LLP, Deloitte consulting LLP, Deloitte Financial Advisory Services LLP, Deloitte Tax LLP, and their subsidiaries), and not by Deloitte & Touche USA LLP. The subsidiaries of the U.S. member firm are among the nation’s leading professional services firms, providing audit, tax consulting, and financial advisory services through nearly 40,000 people in more than 90 cities. Known as employers of choice for innovative human resources programs, they are dedicated to helping their clients and their people excel. For more information, please visit the U.S. member firm’s Web site at http://www.deloitte.com