The MspI restriction polymorphism of the serotonin 2A receptor gene (5HT2A) was typed in populations of the Volga-Ural region (Bashkirs, Chuvashes, Tatars, Udmurts, Maris, Mordovians, Komis, and Russians inhabiting the Republic of Bashkortostan). Population-specific patterns of the main polymorphism indices distribution were established. Specific trends in the changes of genotype and allele frequency of the 5HT2A gene depending on the ethnicity of the population were revealed.