Increasing use of ionizing radiation sources in different spheres of human life dictates the need for investigating the effects of low-dose radiation on mortality and morbidity. The aim of this study was to compare mortality from the most common non-communicable diseases in the cities of Severodvinsk and Arkhangelsk. We analyzed the rates of age- and sex-specific mortality from circulatory system diseases (CSD), malignancies, digestive system disorders, respiratory system diseases, and external causes. CSD-related mortality among men and women past working age was higher in Severodvinsk than in Arkhangelsk (median (Q1; Q3): 3,349 (3,271; 3,458) vs 2,651 (2,618; 2,756), p < 0.012; 1,947 (1,890; 2,022) vs 1,753 (1,727; 1,809), p < 0.012; 292 (281; 342) vs 265 (253; 274), p < 0.025, respectively). For other causes of death, mortality rates in Severodvinsk did not exceed those in Arkhangelsk. Increased mortality from CSD in Severodvinsk cannot be linked to socioeconomic conditions or chemical air pollution because the standard of living is higher in Severodvinsk than in Arkhangelsk, whereas the level of chemical pollution is lower. At the same time, the presence of the nuclear shipyard and radioactive waste repository in Severodvinsk could cause chronic exposure to low-dose radiation. It is important to expand preventive measures aimed at early detection of vascular damage in nuclear workers and general groups of population residing in the vicinity of hazardous radiation sites.