1
                                                                    EXHIBIT 99.1

FOR IMMEDIATE RELEASE



                     GTS Appoints Duncan Lewis as President

LONDON - January 15, 2001 - Global TeleSystems, Inc. ("GTS") (NYSE: GTS; Easdaq:
GTSG; Frankfurt: GTS), the leading pan-European provider of broadband optical
and IP network services, today announced that Duncan Lewis has joined the
company as President and Chief Operating Officer. Lewis, 49, is a recognised
leader in the global data and telecommunications industry, with more than 20
years experience in senior roles across the sector.

Prior to joining GTS, Lewis was Managing Director and Chief Corporate
Development Officer of Equant NV. Equant operates the world's largest global
data network, serving exclusively multinational companies. Lewis had overall
responsibility for day-to-day global operations at Equant as well as the
strategic development of the business. Amongst his other achievements, Lewis was
part of the senior team that brought Equant to profitability within three years
of its start-up and built a customer base that includes around 30% of the Global
1000 companies.

Lewis will report to GTS Chairman and CEO Robert J. Amman and will oversee
day-to-day operations of the company. He will especially focus on expanding
GTS's Broadband Services business into the corporate market through the rapid
development of a sales force and product set that serve the data and network
communications needs of large companies throughout Europe.

The Company has previously announced a restructuring program that includes the
sale of its Central European and Business Services units to focus on building
its Broadband Services business. Amman will now focus on this restructuring. On
successful completion of the restructuring, it is intended that Lewis will be
appointed CEO of GTS and that Amman will become non-executive Chairman.

Amman commented: "We are thrilled to bring in a proven leader of Duncan Lewis'
calibre, experience and track record. GTS has long been Europe's acknowledged
market leader in providing carriers and service providers with broadband and
optical IP services. Duncan is the perfect person to help us rapidly extend and
expand that success into Europe's E.30 billion corporate services market."

Commenting on his appointment, Lewis added: "I chose to join GTS because of its
existing leadership role in Europe's broadband services market and its potential
to extend that success to the corporate market. GTS uniquely combines the
leading European and trans-Atlantic physical network infrastructure; the leading
European Internet backbone; a highly-skilled pan-European workforce and
management group; a stable and high-quality customer base; and significant
recurring revenues. My role is to help GTS quickly and effectively build on
these assets to extend our presence to serve Europe's largest corporations. I am
energised by the prospect and determined that we will succeed."

Prior to Equant, Lewis' senior roles included: Chief Executive Officer, Mercury
Communications; Managing Director, Cable and Wireless Europe, and Business
Networks; and Chief Executive Officer, Granada Media. He has also held various
senior roles at BT, including Director - Procurement, Strategy and Network
Services.


   2


ABOUT GTS (WWW.GTS.COM)

GTS is the leading provider of broadband optical and IP network services across
Europe, serving carriers and corporations with a range of broadband, hosting and
Internet/IP services. As the broadband leader in Europe, the company has the
largest cross-border fiber optic network and the largest Tier-1 Internet
backbone. Additionally, as part of its Business Services unit, which is
currently for sale, GTS serves small and medium sized enterprises (SMEs) in 12
European countries. The company also operates seven city enterprise networks
(CENS), which provide intra-city bandwidth, and trans-Atlantic optical fibre
network facilities connecting Europe and North America. The company has its
headquarters in London. Other corporate offices are located in Washington, D.C.,
Brussels and Cork, Ireland. The company has sales and service operations in a
total of 20 countries.

GTS CONTACTS

Glenn Manoff (Media)
Tel.: 44-207-769-8290; fax: 44-207-769-8084; email: glenn.manoff@gts.com

Jim Shields (Investors)
Tel.: 44-207-769-8264; fax: 44-207-769-8068; email: jim.shields@gts.com

This press release contains certain forward-looking statements within the
meaning of Section 27A of the Securities Act of 1933, as amended, and Section
21E of the Securities Exchange Act of 1934, as amended, which are intended to be
covered by the safe harbors created thereby. Investors are cautioned that all
forward-looking statements involve risks and uncertainties. Although GTS
believes that the assumptions underlying the forward-looking statements
contained herein are reasonable, any of the assumptions could be inaccurate, and
therefore, there can be no assurance that the forward-looking statements
included in this press release will prove to be accurate. In light of the
significant uncertainties inherent in the forward-looking statements included
herein, the inclusion of such information should not be regarded as a
representation by GTS or any other person that the objectives and plans of GTS
will be achieved.

                                      # # #