FORM 6-K

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Report of Foreign Issuer
July 6, 2006

Pursuant to Rule 13a-16 or 15d-16 of
the Securities Exchange Act of 1934

Commission file number: 333-12032

Mobile TeleSystems OJSC

(Exact name of Registrant as specified in its charter)

Russian Federation

(Jurisdiction of incorporation or organization)

4, Marksistskaya Street
Moscow 109147
Russian Federation

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F x   Form 40-F o

Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes o   No x

MTS’ OFFICIAL STATEMENT REGARDING BITEL

MTS PRESS RELEASE. JULY 6, 2006

MOSCOW, RUSSIAN FEDERATION—JULY 6, 2006—MOBILE TELESYSTEMS OJSC (“MTS”—NYSE: MBT), THE LARGEST MOBILE PHONE OPERATOR IN RUSSIA AND THE CIS, ADVISES THAT ANY TRANSACTIONS INVOLVING BITEL ARE ILLEGAL.

In light of the information in the media regarding the decision by the unlawfully appointed management of Bitel to sell off its assets, MTS would like to inform any participants in this transaction that we reserve the right to institute legal proceedings against them.

MTS considers the control over Bitel by Reservspetzmet as being illegal, and the Company continues to successfully defend its rights in courts.

Therefore, given the fact that Reservspetzmet had illegally taken control of Bitel, any operations involving Bitel, including those involving all or some assets of the company, have no legal effect and will be contested in court.

Continuing to defend its rights over Bitel in courts, MTS will inform the public on a regular basis of the progress made in the legal proceedings.

***

For further information, please contact:

***

Mobile TeleSystems OJSC (“MTS”) is the largest mobile phone operator in Russia and the CIS. Together with its subsidiaries, the Company services over 62.89 million subscribers. The regions of Russia, as well as Belarus, Turkmenistan, Ukraine, and Uzbekistan, in which MTS and its associates and subsidiaries are licensed to provide GSM services, have a total population of approximately 233.1 million. Since June 2000, MTS’ Level 3 ADRs have been listed on the New York Stock Exchange (ticker symbol MBT). Additional information about MTS can be found on MTS’ website at www1.mtsgsm.com.

***

Some of the information in this press release may contain projections or other forward-looking statements regarding future events or the future financial performance of MTS, as defined in the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. You can identify forward looking statements by terms such as “expect,” “believe,” “anticipate,” “estimate,” “intend,” “will,” “could,” “may” or “might,” and the negative of such terms or other similar expressions. We wish to caution you that these statements are only predictions and that actual events or results may differ materially. We do not intend to update these statements to reflect events and circumstances occurring after the date hereof or to reflect the occurrence of unanticipated events. We refer you to the documents MTS files from time to time with the U.S. Securities and Exchange Commission, specifically the Company’s most recent Form 20-F. These documents contain and identify important factors, including those contained in the section captioned “Risk Factors” that could cause the actual results to differ materially from those contained in our projections or forward-looking statements, including, among others, potential fluctuations in quarterly results, our competitive environment, dependence on new service development and tariff structures, rapid technological and market change, acquisition strategy, risks associated with telecommunications infrastructure, risks associated with operating in Russia, volatility of stock price, financial risk management and future growth subject to risks.

***

WWW.MTS.RU

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: July 6, 2006

2