March 2004

30.03.2004
Financial Results for the Fourth Quarter and Full-Year Ended December 31, 2003

Moscow, Russian Federation — March 30, 2004 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and Ukraine, today announces its financial and operating results for the fourth quarter and full-year ended December 31, 20031.

29.03.2004
April 1st on 1008

MTS invites you to a hearty laugh with practical jokes, anecdotes, proverbs, amusing histories and indecent ditties for April 1st!

26.03.2004
MTS Opens Conversion Between Local Shares, GDRs and ADRs

Moscow, Russian Federation — March 26, 2004 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and Ukraine, announces that it has completed all the formalities required to open conversion of the company’s local shares and GDRs into ADRs.

25.03.2004
Conquer Your Fears!

“Fear Factor”: a New TV-SMS Game on NTV!

25.03.2004
Stop Queuing for Cinema Tickets!

Send an SMS to 9090.

24.03.2004
The first TV-SMS “Adventures of Ponaroshku” game on MTV-Russia!

Mobile TeleSystems, in conjunction with the MTV channel, is pleased to bring you the TV-SMS “Adventures of Ponaroshku” show.

22.03.2004
19.03.2004
MTS Increases Ownership in its Novosibirsk Subsidiary

Moscow, Russian Federation — March 19, 2004 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and Ukraine, announces that it has acquired an additional 11% of Siberian Cellular Systems-900 (SCS-900). As a result of this transaction, MTS now owns 99.5% of the company.

17.03.2004
16.03.2004
12.03.2004
MTS Completes an Important Step Towards Providing for GDR Fungibility

Moscow, Russian Federation — March 12, 2004 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and Ukraine, announces that the Russian Federal Commission for Securities Market (FCSM) has approved an increase in the number of the company’s shares to be available for trading outside of Russia by 22.5% of total.

04.03.2004
MTS Announces Subscriber Growth Numbers For February 2004

Moscow, Russian Federation — March 04, 2004 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and Ukraine, announces that its consolidated subscriber base reached 18.25 million users on February 29, 2004.

02.03.2004
Test Launch of GPRS–Roaming is Prolonged to March 10!

Ladies and Gentlemen! MTS announces that its GPRS–roaming test launch will be prolonged until March 10.

02.03.2004
Unlimited tariff to Businessmen and women

MTS is delighted to announce that the subscription renewal of its “Exclusive” unlimited tariff plan from February 27, 2004.

Contact investor relations:

+ 7 495 223 20 25 ir@mts.ru

MTS Investor Relations
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