Moscow, Russian Federation – Mobile TeleSystems OJSC (“MTS” – NYSE: MBT), the leading telecommunications operator in Russia and the CIS, announces that it has acquired a 35.59% stake in Teleservice OJSC (“Teleservice”), broadband and Pay-TV provider in Voronezh, from a private investor. Upon completion of the transaction, MTS Group’s stake in Teleservice will increase up to 89.88%

For further information, please contact in Moscow:

Joshua B. Tulgan

Director, Corporate Finance & Investor Relations

Mobile TeleSystems OJSC

Tel: +7 495 223 2025

E-mail: ir@mts.ru