TORONTO, ONTARIO, December 3, 2007 - Constellation Software Inc. ("Constellation") (TSX:CSU) announced today that it has acquired the business of Vermont-based Systems & Software Incorporated ("SSI").

As a result of the purchase, SSI and its flagship enQuesta CIS will become part of the portfolio of Customer Information Systems (CIS) software solutions for Constellation's Harris Operating Group ("Harris"). SSI will operate as an independent division of Harris and will continue to sell, develop and enhance enQuesta CIS and provide support and service to SSI customers.

Harris CEO Jeff Bender stated, "We are very pleased with our ability to complete the purchase of SSI. SSI and enQuesta will be great additions to our Customer Choice strategy and provide Harris and its customers with unparalleled choice among the best solutions available in the marketplace. Harris provides the level of corporate and financial stability as well as market leadership that the CIS market needs and wants. Our business model positions us to succeed for our customers and our employees - providing the best of both worlds."

"The acquisition of SSI, with just under 90 employees, is a good example of Constellation's business model," commented John Billowits, Chief Financial Officer of Constellation. "As one of our larger tuck-in acquisitions in the utility space, SSI will provide Harris with another key platform to complement its growth strategy."

"We are pleased with the amount of capital we have deployed in 2007," said Bernard Anzarouth, VP, Business Development of Constellation. "Including companies acquired in Q4, we have deployed US$52M on acquisitions in 2007. This is the most capital we have deployed on acquisitions in any one year."

About Constellation
Constellation's common shares are listed on the Toronto Stock Exchange under the symbol "CSU". Constellation Software is an international provider of market leading software and services to a number of industries across both the public and private sectors. Constellation acquires, manages and builds vertical market software businesses that provide mission-critical software solutions to address the specific needs of its customers in those industries.

About Harris
Harris is a wholly-owned subsidiary of Constellation and is a leading provider of financial management and Customer Information Systems (CIS) software solutions. Since 1976, Harris has focused on providing feature-rich and robust turnkey solutions to all levels of local government, public power and water entities as well as school districts throughout North America. Harris' focus is on creating long-term relationships with our customers and ensuring that we meet the changing needs of our customers over time. For further information on Harris Computer Systems, please visit our website at www.harriscomputer.com.

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