Fatty acid composition of lecithin and cholesterol esters was studied in high density lipoproteins obtained from blood serum of 20 male volunteers, 10 pigs, 10 rats and 30 burbots (Lota lota); the study was carried out using isolation (precipitation) of the lipoproteins, thin-layer chromatography of lipoproteins and gas liquid chromatography of fatty acids. The findings suggest that the fatty acid composition of the preparations studied may serve as a more exact index of lipid metabolism than the serum levels of individual lipoproteins.