Mammals are distributed everywhere on the territory of the Pavlodar region (North-East of Kazakhstan). The narrow-crusted vole and steppe mouse species dominate in the anthropogenic habitats. Small mammals live in the conditions of emission of large enterprises of heavy industry. There are oxides of sulfur (IV) and nitrogen (IV), carbon monoxide (II), solid fluorides, hydrogen fluoride, benz(a)pyrene; V, Cr, Mn, Fe, Ni, Cu, Zn, Pb near large factories and highways. Animals receive toxic substances from food through trophic levels and through respiration. Insectivorous mammals suffer from pollution more than rodents. Fluoride accumulates in the bone tissue. Heavy metals are present in the coat, liver, kidneys, lungs, genitals and musculoskeletal system of mammals. The most dangerous for animal health is benz (a) pyrene, which is a mutagen in small quantities. The degree of influence of toxic substances decreases with the remoteness of the habitat from the sources of pollution.