Exhibit 99.1

NEWS RELEASE

FOR IMMEDIATE RELEASE

CSG SYSTEMS COMPLETES ACQUISITION OF DATAPROSE, INC.

ENGLEWOOD, Colo. (May 1, 2008) — CSG Systems International, Inc. (NASDAQ: CSGS), a leading provider of customer care and billing solutions, today announced that it has completed the acquisition of DataProse, Inc. CSG initially announced the acquisition on April 17, 2008.

About CSG Systems

Headquartered in Englewood, Colorado, CSG is a leading provider of outsourced solutions that facilitate customer interaction management on the behalf of our clients, generating a large percentage of revenues from the North American cable and Direct Broadcast satellite (“DBS”) communications markets. Our solutions also support an increasing number of other industries such as financial services, utilities, telecommunications, and home security. Our solutions manage key customer interactions such as set-up and activation of customer accounts, sales support and marketing, order processing, invoice calculation (i.e., customer billing), production and mailing of monthly customer invoices, management reporting, electronic presentment and payment of invoices, automated and interactive messaging, and deployment and management of the client’s field technicians to the customer’s home. Our unique combination of solutions, services, and expertise ensure that our clients can rapidly launch new service offerings, improve operational efficiencies, and deliver a high-quality customer experience in a competitive and ever-changing marketplace. For more information, visit our website at www.csgsystems.com.

Forward-Looking Statements

This news release contains forward-looking statements as defined under the Securities Act of 1933, as amended, that are based on assumptions about a number of important factors and involve risks and uncertainties that could cause actual results to differ materially from what appears in this news release. These factors include, but are not limited to: 1) the concentration of approximately two-thirds of CSG’s revenues with four clients; as a result, the loss of business from any one of those clients could potentially have a material adverse impact to CSG’s financial results; 2) continued market acceptance of CSG’s Advanced Convergent Platform (ACP) and related products and services; 3) CSG’s ability to continuously develop and enhance products in a timely, cost-effective, technically advanced and competitive manner; 4) CSG’s dependency on the North American communications industry; as a result, key market factors such as further industry consolidation, new market entrants that may not be clients of CSG, economic conditions,

and/or the financial status of CSG clients may affect CSG’s ability to maintain and expand market share; 5) increasing competition in our market from companies of greater size and with broader presence in the communications sector, thus exerting greater influence over client buying decisions; 6) CSG’s ability to successfully integrate and manage acquired businesses, technology or assets to achieve the expected strategic, operating and financial goals established for such acquisitions; 7) CSG’s continued ability to protect its intellectual property rights; and 8) CSG’s dependency on a variety of computing environments and communications networks, thus subjecting CSG to the risks of extended interruptions, outages, unauthorized access and corruption of data. This list is not exhaustive and readers are encouraged to review the additional risks and important factors described in CSG’s reports on Forms 10-K and 10-Q and other filings made with the SEC.

For more information, contact:

Media Relations:

Elise Brassell

CSG Systems

Phone: (303) 804-4962

E-mail: elise_brassell@csgsystems.com

Investor Relations:

Roger Metz

CSG Systems

Phone: (303) 804-4082

E-mail: roger_metz@csgsystems.com

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