Relevance. Both Russian and foreign researchers pay attention to the mental disorders in people with a history of accidental radiation exposure. A wide range of mental pathologies have been observed among the Chernobyl NPP clean-up workers, victims of the accident at the Fukushima Daiichi NPP, etc.Intention – To assess primary incidence of mental disorders and behavioral disorders in residents of the municipal areas of the Chelyabinsk region affected by radioactive contamination.Methodology. Primary incidence rates of mental disorders and behavioral disorders (F00–09, F20–99 ICD-10) were assessed for the period from 2005 to 2018 in residents of municipal areas of the Chelyabinsk regions (Kunashaksky, Krasnoarmeysky, Argayashsky, Kaslinsky, Sosnovsky districts) affected by radioactive contamination in 1949–1951 and 1957 as a result of the activities of the “Mayak” production association. These data were compared to that from non-contaminated Etkulsky district with similar population and economic activity. Mental disorders were classified according to the groups of the chapter V “Mental and behavioral disorders” of the International Classification of Diseases of the 10th revision (ICD-10). Incidence was calculated per 10 thousand population (0/000). Descriptive analysis of the registered primary incidence of mental disorders in residents of these districts of the Chelyabinsk region is presented.Results and discussion. The primary incidence rate of mental disorders in the Chelyabinsk region (49.1 ± 3.6) 0/000 significantly (p < 0.001) exceeds those in the Sverdlovsk (30.3 ± 4.2), Kurgan (30.2 ± 6.9) 0/000 regions and overall estimates for the Russian Federation (32.9 ± 3.8) 0/000 . In the remote period, primary incidence rates of mental disorders in the residents of some radioactively contaminated districts were higher vs Etkulsky district, but significantly lower than overall rates in the Chelyabinsk region (p < 0.001). Taking into account the territorial distribution of the exposed residents and their offspring in the Chelyabinsk region, mental retardation in residents of the Kunashak district should be closely monitored.Conclusion. Mental morbidity in areas accidentally contaminated more than 70 years ago now reflects the general trend of deterioration in the mental health of the population of the Chelyabinsk region. It can be assumed that the incidence of mental disorders in the population of the Chelyabinsk region is determined by a constellation of interacting factors (socio-economic, personal-psychological, radiation, informational and others), among which socially determined mechanisms of the mental pathology prevail.