May 2007

31.05.2007
Financial Results for the First Quarter Ended March 31, 2007

MOSCOW, RUSSIAN FEDERATION — MAY 31, 2007 — MOBILE TELESYSTEMS OJSC («MTS» — NYSE: MBT), THE LARGEST MOBILE PHONE OPERATOR IN RUSSIA AND THE CIS, ANNOUNCES ITS FIRST QUARTER 20071 FINANCIAL AND OPERATING RESULTS.

30.05.2007
MTS Announces Change to 2006 Reported Financial Results

MOSCOW, RUSSIAN FEDERATION — MAY 30, 2007 — MOBILE TELESYSTEMS OJSC («MTS» — NYSE: MBT), THE LARGEST MOBILE PHONE OPERATOR IN RUSSIA AND THE CIS, ANNOUNCES THAT IT WILL RECORD A CHARGE TO NON-OPERATING EXPENSES FOR THE YEAR ENDED DECEMBER 31, 2006 IN RELATION TO A $170 MILLION PUT OPTION HELD BY NOMIHOLD SECURITIES INC. («NOMIHOLD»).

29.05.2007
First Quarter 2007 Financial Results Announcement and Conference Call

The management of Mobile TeleSystems (MTS) will be holding a conference call to discuss the Company’s First Quarter 2007 Financial and Operating Results on Thursday, May 31, 2007.

18.05.2007
MTS Announces Subscriber Growth Numbers for April 2007

MOSCOW, RUSSIAN FEDERATION — MAY 18, 2007 — MOBILE TELESYSTEMS OJSC («MTS» — NYSE: MBT), THE LARGEST MOBILE PHONE OPERATOR IN RUSSIA AND THE CIS, ANNOUNCES THAT ITS CONSOLIDATED SUBSCRIBER BASE REACHED 74.52 MILLION USERS ON APRIL 30, 2007.

15.05.2007
MTS Announces Recommended Amount of Dividends and Adoption of a Dividend Policy

MOSCOW, RUSSIAN FEDERATION — MAY 15, 2007 — MOBILE TELESYSTEMS OJSC («MTS» — NYSE: MBT), THE LARGEST MOBILE PHONE OPERATOR IN RUSSIA AND THE CIS, ANNOUNCES THE RECOMMENDED AMOUNT OF DIVIDENDS AND THE ADOPTION OF A DIVIDEND POLICY.

Contact investor relations:

+ 7 495 223 20 25 ir@mts.ru

MTS Investor Relations
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