Ad Hoc Notice

October 19, 2009

Moscow, Russian Federation — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and the CIS, affirms guidance statements issued today at the MTS Analyst and Investor Day by the management of the Company.

MTS confirms that Group revenue is expected to reach $8.25 bln for the FY 2009, assuming stability of exchange rates of national currencies and stable macroeconomic conditions in the operating markets. The Company’s OIBDA margin for the FY 2009 is expected to be in the high 40%s range. MTS also raised its CAPEX guidance for the FY 2009 from $1.5 bln to $1.8 bln primarily due to Russian ruble appreciation, as well as additional spending in Central Asian markets to accommodate increasing traffic.

MTS continues to anticipate single-digit year-over-year ruble revenue growth in its Russian business unit in 2009 and a single-digit year-over-year revenue reduction in hryvna revenue in Ukraine in 2009, provided the macroeconomic environment remains stable relative to the current period.

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For further information, please contact in Moscow:

Joshua B. Tulgan

Director, Investor Relations

Mob: +7 985 220 4208

Department of Investor Relations

Mobile TeleSystems OJSC

Tel: +7 495 223 2025

E-mail: ir@mts.ru

Learn more about MTS. Visit the official blog of the Investor Relations Department at www.mtsgsm.com/blog/

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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 96.17 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.

MOBILE TELESYSTEMS OJSC

By:

/s/ Mikhail Shamolin

Name:

Mikhail Shamolin

Title:

CEO

Date:   October 19, 2009