Migrant residential concentration areas have been a significant focus for research, but academic attention has primarily centered on their effects rather than how they form. There is some research considering the discrete factors of such areas’ emergence, but these factors are rarely fused into a comprehensive explanation with a description of specific mechanisms in operation. Even less is known about the formation of migrant residential concentration areas in postsocialist cities. The few studies in existence leave the impression that such areas emerge around bazaars by default. In this article, based on a multicase study (N = 37) conducted in the 15 largest Russian cities, we argue that although there is a pattern of migrant residential concentration areas’ emergence in postsocialist cities, this process takes place only in the presence of a combination of seven factors. The article presents these factors and describes an ideal type of a migrant residential concentration area in a Russian city and mechanisms of its emergence. The article concludes with the comparison of the postsocialist pattern with other types of migrant residential concentration and hypothesizing on how the Russian case differs from the other postsocialist cases in Central and Eastern Europe.