The data on mitochondrial DNA diversity in seven local populations (villages) and four territorial groups of Tatars of the Tobol-Irtysh basin are presented. In the Turkic-speaking populations from the Tobol and Irtysh river basins, high levels of intergroup and interpopulation mtDNA variation were observed. It was demonstrated that genetic diversity of the territorial groups of Tatars of the Tobol-Irtysh basin resulted from various interethnic relationships and different ethnic components integrated into these groups.