Moscow, April 29, 2003. Mobile TeleSystems OJSC ("MTS" - NYSE: MBT), the largest mobile phone operator in Russia and Central and Eastern Europe , today announced preliminary unaudited revenue and subscriber numbers for the fourth quarter and the full year 2002.

Revenues for the year ended December 31, 2002 were $1.36 billion, a year-on-year increase of 52.5%. Fourth quarter revenues were $410 million, a 58.6% increase on the same quarter in 2001, and a 5.5% increase on the previous quarter. Average monthly revenue per user (ARPU) was $21.2 in the fourth quarter, and $22.9 for the full year.

Mikhail Smirnov, President of MTS, said: "I'm pleased to report another year of strong revenue and subscriber growth for MTS. This year we concentrated on two main areas, namely expansion in Russia's regions and into some of our neighboring countries, and the consolidation and strengthening of our existing operations in Russia. As a result of this, we have managed to increase our subscriber numbers substantially and to grow revenues".

MTS' churn rate in the fourth quarter was at 10.1% and at 33.9% for the full year. The management believes that the increase in the Company's churn rate in 2002 is consistent with the general industry trend in Russia. Nevertheless, the Company continues to implement programs to encourage subscriber loyalty.

During the last quarter of 2002, MTS experienced an accelerated growth in new subscriptions as 1.22 million new customers were added on a net basis . However, as the bulk of new additions took place towards the end of the quarter the subscriber growth during the quarter did not significantly affect revenues.

MTS also experienced an increase in average monthly usage per subscriber (MOU) in 2002 to 159 minutes compared to 157 minutes in 2001. In the fourth quarter of 2002 MOU was at 175 minutes.

The Company's audited results for the fourth quarter and full year 2002 prepared under U.S. GAAP are expected to be announced on May 20, 2003. Dial-in numbers for the management conference call will be circulated prior to the announcement date.

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Mobile TeleSystems OJSC (or "MTS") is the largest mobile phone operator in Russia, and Central and Eastern Europe in terms of subscribers. Together with its subsidiaries, the company services over 9.8 million subscribers. The 58 regions of Russia as well as in Belarus and Ukraine in which MTS and its subsidiaries are licensed to provide GSM services have a total population of approximately 169.2 million. Since June 2000, MTS' shares have been listed on the New York Stock Exchange with the ticker symbol MBT. Additional information about MTS can be found on MTS' website at www.mtsgsm.com

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For further information contact:

Mobile TeleSystems, Moscow
Investor Relations
Andrey Braginski
tel: +7095 911 6553
e-mail: ir@mts.ru

Press Secretary
Eva Prokofieva
tel.: +7095 737 4530
e-mail: eva@mts.ru

Gavin Anderson & Company, London
Halldor Larusson
tel: +44 (0) 20 7554 1400

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Some of the information in this press release may contain projections or other forward-looking statements regarding future events or the future financial performance of MTS, as defined in the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. You can identify forward looking statements by terms such as "expect," "believe," "anticipate," "estimate," "intend," "will," "could," "may" or "might" the negative of such terms or other similar expressions. We wish to caution you that these statements are only predictions and that actual events or results may differ materially. We do not intend to update these statements to reflect events and circumstances occurring after the date hereof or to reflect the occurrence of unanticipated events. We refer you to the documents MTS files from time to time with the U.S. Securities and Exchange Commission, specifically, the Company's most recent Form 20-F, as amended. These documents contain and identify important factors, including those contained in the secton captioned "Risk Factors," that could cause the actual results to differ materially from those contained in our projections or forward-looking statements, including, among others, potential fluctuations in quarterly results, our competitive environment, dependence on new service development and tariff structures; rapid technological and market change, acquisition strategy, risks associated with telecommunications infrastructure, risks associated with operating in Russia, volatility of stock price, financial risk management, and future growth subject to risks.