Kyivstar is the largest mobile network operator in Ukraine, it had 25.4 million subscribers at the end of June 2014 and thus a 42 percent market share. It served 24,944,592 subscribers as of October 2010. Kyivstar's wireless network operates using the GSM standard and provides coverage accessible by approximately 99% of the Ukrainian population.
On 5 February 2015 Kyivstar officially gave up its base stations in territory controlled by pro-Russian separatists during the War in Donbass. The following months the company accused the separatists Donetsk People's Republic of setting up its own mobile network operator using these base stations. On 18 April 2015 pro-Russian separatist leader Aleksandr Zakharchenko issued a decree stating that all equipment that Kyivstar gave up falls under the control of the separatists in order to “meet the needs of the population in the communication services”. Kyivstar's president Petro Chernyshov labelled the Donetsk People's Republic operator "It's just robbery".