The influence of the chemical composition of water in the Republic of Altai (RA) on medical-demographic indices has been studied. It has been found that the water is poorly mineralized, the fluorine content in it is three times lower than the optimal one, and the pollution of the water with toxicants 3.3—4.6 times exceeds the maximum permissible level. Significant correlation coefficients (р < 0.05) are revealed between the excess over the maximum permissible concentrations of toxicants in the drinking water and infant mortality; total chemical pollution of water and total adult morbidity, optimality index of the drinking water and morbidity with new-onset circulatory diseases, fluorine content in the drinking water and the level of congenital defects, water mineralization and hardness and the oncological mortality level in RA rural regions.