The article is devoted to the analysis of the data of the population censuses of the Soviet period in the context of the formation of the urban Kazakh population of East Kazakhstan. On this basis, the main stages are highlighted, reflecting the characteristics of a particular historical segment. Each stage is given a historical and demographic characteristic, its influence on the dynamics of the formation of the population of the region is determined. It was found that the general republican tendencies were reflected in East Kazakhstan, and regional features were also noted. The population of the region is considered as consisting of two main ethnic groups - Kazakhs and Russians, but the share of representatives of other ethnic groups is also taken into account. Conclusions are made that in the 1960s-80s in the differences in demographic vectors of the main ethnic groups are increasingly manifested, the tendency of urbanization of the Kazakh ethnos is gradually forming, since this period Kazakhs are increasingly becoming an urban nation.