The current linguistic situation in Ukraine, which has evolved over the course of several centuries, presents itself as a unique subject for linguistic description and study, differing substantially from analogous examples elsewhere in the Slavic world. Given article deals with still not described in details topic in modern Russian and Slavic Studies, that is functioning of Russian in the capital city – Kyev and the large cities of Ukraine, which de facto have always been and still stay Russian speaking with the exception of Western regions of the country. The study is also devoted to viewing such a phenomenon as a form of linguistic interference within the mixing of two closely related languages.