Financial results for the first quarter ended March 31, 2008

20 May 2008

Moscow, Russian Federation — Mobile TeleSystems OJSC («MTS» — NYSE: MBT), the largest mobile phone operator in Russia and the CIS, announces its first quarter¹ 2008 financial and operating results.

¹ Based on unaudited consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States of America («US GAAP»).