The effect of experimental hyperlipidemia on functional activity of macrophages was studied in CBA and C57Bl/6 mice resistant and sensitive to the formation of aorta lesions, respectively. Two-month atherogenic diet increased the content of cholesterol in the serum and cells of peritoneal exudate in mice of both strains. In parallel, production of nitrites and 5'-nucleotidase activity in peritoneal macrophages increased, while parameters of phagocytosis, pinocytosis, and NBT test remained unchanged. Changes in the state of macrophages can be explained by increased cholesterol content. The absence of differences in functional activity of macrophages in CBA and C57Bl/6 mice indicates that the observed shifts are insignificant for the development of fatty streaks in the aorta.