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Exhibit 99.1

CERTIFICATION OF CHIEF EXECUTIVE OFFICER
PURSUANT TO
18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

        I, George A. Hallenbeck, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that the Annual Report of Evolving Systems, Inc. on Form 10-K for the year ended December 31, 2002 fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and that information contained in such Form 10-K fairly presents in all material respects the financial condition and results of operations of Evolving Systems, Inc.

/s/ George A. Hallenbeck George A. Hallenbeck
Chief Executive Officer and Chairman of the Board of Directors
March 28, 2003

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Exhibit 99.1