Moscow, Russian Federation – November 15, 2005 – Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and the CIS, announces the appointment of Grzegorz Esz to the position of Deputy Chief Marketing Officer.

Grzegorz Esz was appointed the Company’s Deputy Chief Marketing Officer at the beginning of this month. He is responsible for such key marketing functions as tariff policy, value-added products and services development and marketing communications.

“Grzegorz possesses a wealth of experience in the wireless industry, and I am certain that he will make a significant contribution in further strengthening MTS’ marketing efforts. The appointment of Grzegorz will add a new perspective to our management team in working with subscribers in a mature market,” said MTS’ President and CEO, Vassily Sidorov.

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Biography

Grzegorz Eszwas born in 1972. He is a graduate of the Warsaw University of Technology and the London Business School (Executive MBA). Mr. Esz has worked in the IT and Telecommunications fields for ten years and has received awards for his innovations and creative solutions. Most recently, he was the Deputy Chief Marketing Officer at ERA Company, the largest GSM operator in Poland.