Breast cancer is the most common cause of cancer death in the Republic of Buryatia as a whole and among urban population (13.3 % and 16.0 %, respectively), and the second place belongs to rural population (11.8). Standardized mortality rates in the Republic of Buryatia (15.5±0.9) are 9.9% lower than the average for Russian Federation (17.0±0.1). The relationship between the national composition of the population of the municipal districts of Buryatia and breast cancer mortality rate has been found. Breast cancer mortality rates are higher for newcomers than for indigenous population (2.4 times higher among urban population and 2.3 times among rural population). Breast cancer mortality rate is expected to be decreased by 9.9% in the Republic as a whole, by 10.0% among urban population and also stability of mortality among rural population (2.3%).