April 2005

27.04.2005
MTS’ Intranet Roaming Zone: Chita Region

From April 27, 2005, the Chita region will be integrated into MTS’ intranet roaming zone.

26.04.2005
“MTS. Team” — a Simple Solution for Small Organizations

From April 26, 2005, MTS offers its users in the Moscow region the new “Team” corporate tariff plan.

19.04.2005
MTS Announces AGM Date and Nominations for the Company’s Board of Directors

Moscow, Russia — April 19, 2005 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and the CIS, announces the date of the annual general meeting of shareholders and the nominees for the Company’s Board of Directors.

14.04.2005
Business 200: MTS’ New Tariff Plan

MTS’ new tariff plan, Business 200, will be launched on April 14, 2005, providing its users in the Moscow region with all the benefits of the Business tariff group.

11.04.2005
07.04.2005
MTS Announces Subscriber Growth Numbers for March 2005

Moscow, Russian Federation — April 07, 2005 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and the CIS, announces that its consolidated subscriber base reached 38.69 million users on March 31, 2005.

Contact investor relations:

+ 7 495 223 20 25 ir@mts.ru

MTS Investor Relations
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