Moscow, Russian Federation – Mobile TeleSystems OJSC (the “Company” or “MTS” – NYSE: MBT), the largest mobile phone operator in Russia and the CIS, announces that it has sent an irrevocable notice to ING Bank, N.V. (London branch), the Agent of the Lenders under the syndicated loan agreement originally signed in May 2009 and amended in June 2009, regarding the voluntary prepayment of the loan.

In accordance with the terms of the loan agreement, MTS will prepay without any penalties the principal and loan interest amounts on facility A of $373.8 million and on facility B of ˆ247.6 million.

Mr. Alexey Kornya, acting Vice President and Chief Financial Officer at MTS, commented: “The decision to repay the syndicated loan is reflective of our efforts to reduce the Company’s debt servicing costs and better balance our debt portfolio with our revenues. We are also seeing positive developments in the capital markets with declining interest rates and longer term funding becoming available both in Russia and abroad. Given MTS’ outstanding record as a borrower and strong financials, we feel we can further optimize our debt portfolio.”

The original syndicated loan for $360.0 million and ˆ238.1 million carried a three-year maturity and an interest rate of LIBOR+6.5%. The facility was to be repaid in three semiannual installments after a two-year grace period. The proceeds of the loan were used to refinance the $630 million three-year tranche of MTS’ $1.3 billion syndicated loan, which was originally signed in April 2006, as well as for general corporate purposes.