Exhibit 99.01

                                  CERTIFICATION
           PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002
            (SUBSECTIONS (a) AND (b) OF SECTION 1350, CHAPTER 63 OF
                         TITLE 18, UNITED STATES CODE)

     Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 (Subsections (a)
and (b) of Section 1350, Chapter 63 of Title 18, United States Code), the
undersigned officer of T-Mobile USA, Inc., a Delaware corporation (the
"Company"), does hereby certify, to such officer's knowledge, that:

     The Annual Report on Form 10-K for the year ended December 31, 2002
(the "Form 10-K") of the Company fully complies with the requirements of Section
13(a) or 15(d) of the Securities Exchange Act of 1934 and the information
contained in the Form 10-K fairly presents, in all material respects, the
financial condition and results of operations of the Company.

Dated: March 10, 2003                       By: /s/ John W. Stanton
                                            ------------------------------------
                                            Name:  John W. Stanton
                                            Title: Chairman



     The foregoing certification is being furnished solely pursuant to Section
906 of the Sarbanes-Oxley Act of 2002 (Subsections (a) and (b) of Section 1350,
Chapter 63 of Title 18, United States Code) and is not being filed as part of
the Form 10-K or as a separate disclosure document.