First Quarter 2009 Financial Results Announcement and Conference Call

Please note that the conference call will start at:

18:00 hrs (Moscow time)
15:00 hrs (London time)
10:00 hrs (US Eastern time)

To take part in the conference call, please dial one of the following telephone numbers, quoting the Company’s name, MTS:

From the US:               + 1 480 629 9560
From the UK:               + 44 207 190 1598 
International:               + 44 207 190 1598

The conference call will also be available at: http://www.mtsgsm.com/news/reports/ via audio webcast.

The earnings release will be posted approximately three hours prior to the conference call and the management’s slide presentation will be posted approximately one hour prior to the conference call at: http://www.mtsgsm.com/news/reports/.

A replay of the conference call will be available on the following telephone numbers from May 22 (from approximately 23:00 hrs Moscow time/20:00 hrs London time/15:00 hrs US Eastern time) to June 1, 2009:

From the US:               + 1 303 590 3030                 PIN 4080932#
From the UK:               + 44 207 154 2833               PIN 4080932# 
International:               + 44 207 154 2833               PIN 4080932#

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For further information, please contact:

Mobile TeleSystems, Moscow
Investor Relations
Tel: +7 495 223 2025
E-mail: ir@mts.ru

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Mobile TeleSystems OJSC (“MTS”) is the largest mobile phone operator in Russia and the CIS. Together with its subsidiaries, the Company services over 92.19 million subscribers. The regions of Russia, as well as Armenia, Belarus, Turkmenistan, Ukraine, and Uzbekistan, in which MTS and its associates and subsidiaries are licensed to provide GSM services, have a total population of more than 230 million. Since June 2000, MTS’ Level 3 ADRs have been listed on the New York Stock Exchange (ticker symbol MBT). Additional information about MTS can be found on MTS’ website at www.mtsgsm.com.

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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,” and 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 and the CIS, volatility of stock price, financial risk management and future growth subject to risks.