Moscow, Russia — April 30, 2004 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and Ukraine, announces the calling of the annual general meeting of shareholders (AGM) and the recommended amount of dividends.

At the Board of Directors (BoD) meeting yesterday, the calling of the annual general meeting of shareholders was scheduled for June 24, 2004.

The Company’s BoD recommended the AGM approve annual dividends of RUR 3.20 per ordinary MTS share¹ (approximately $2.22 per ADR²) for the 2003 fiscal year, amounting to a total of RUR 6.38 billion ($221.14 million)³. The record date for the Company’s share- and ADR-holders entitled to participate in the AGM and to receive dividends was set for May 10, 2004.

Other issues entered by MTS’ BoD into the AGM agenda include the election of the BoD and Review Commission, the approval of the Company’s Auditor and adoption of amendments into MTS’ Charter.

_______________________________________
¹ The exact amount to be paid is RUR 3.20217480 per ordinary share.
² According to Russia’s Central Bank exchange rate of 28.86 RUR/$ as of April 29, 2004.
³ The amount is 48.0% of the Company’s net income in 2003 in accordance with the RAS and 42.8% of net income under US GAAP.

***

For further information, contact:

Mobile TeleSystems, Moscow
Investor and Public Relations
Andrey Braginski
tel: +7 095 911 6553
e-mail: ir@mts.ru

***
Mobile TeleSystems OJSC (or “MTS”) is the largest mobile phone operator in Russia and Ukraine. Together with its subsidiaries, the company services over 19.2 million subscribers. The 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 200.6 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.

***
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. These documents contain and identify important factors, including those contained in the section 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.