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                                                                    EXHIBIT 23.1

               CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS


     We consent to the reference to our firm under the caption "Experts" in
Pre-Effective Amendment No. 1 to the Registration Statement on Form S-3 (File
No. 333-83307) and related Prospectus of Global TeleSystems Group, Inc. and to
the incorporation by reference therein of our report dated March 8, 1999, with
respect to the consolidated financial statements and schedules of Global
TeleSystems Group, Inc. included in its Annual Report on Form 10-K for the year
ended December 31, 1998, filed with the Securities and Exchange Commission.


                                            /s/  Ernst & Young LLP

Vienna, Virginia

October 6, 1999