Moscow, Russian Federation – Mobile TeleSystems OJSC (“MTS” or the “Company” – NYSE: MBT), the leading telecommunications provider in Russia and the CIS, announces that, pursuant to an Instrument of Resignation, Revocation, Appointment and Acceptance dated February 28, 2011 (the “Instrument”) (i) The Bank of New York Mellon resigned as trustee, registrar and paying agent under the indenture dated as of January 28, 2005 (the “Indenture”) between Mobile TeleSystems Finance S.A.¹ ( the “Issuer”), the Company, and The Bank of New York Mellon (formerly JPMorgan Chase Bank, N.A.), pursuant to which the Issuer’s $400,000,000 8.00% Notes due 2012 were issued; and (ii) Wilmington Trust Comany was appointed, and accepted its appointment, as trustee, registrar and paying agent under the Indenture.

In addition, pursuant to the Instrument, The Bank of New York Mellon (Luxembourg) S.A. resigned as Luxembourg paying agent, and Wilmington Trust SP Services (Luxembourg) S.A. was appointed, and accepted its appointment, as Luxembourg paying agent.

¹A société anonyme duly organized and existing under the laws of Luxembourg and a wholly owned subsidiary of the Company.