Moscow, Russian Federation — January 17, 2005 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT) today announces its plans to raise financing through the placement of senior unsecured USD-denominated eurobonds issued under Rule 144A/Regulation S.

The notes will be issued through MTS’ 100% beneficially-owned subsidiary, Mobile TeleSystems Finance S.A., a company organized under the laws of Luxembourg, and will be guaranteed by MTS. The notes will be offered and sold outside the United States in offshore transactions in reliance on Regulation S under the U.S. Securities Act and in the United States to “qualified institutional buyers” (as defined in Rule 144A under the U.S. Securities Act) in reliance on Rule 144A.

The size of the issue and final terms of the transaction will depend upon market conditions.

The proceeds are expected to be used to refinance certain existing short-term debt and for general corporate purposes, including for potential acquisitions and for potentially increasing MTS’ interests in certain mobile cellular telecommunications providers.