Results are presented on the study of lipid metabolism in normal individuals of different are groups with reference to the hereditary taintness as to ischaelic heart disease, and the results of correlation analysis of the level of some lipid indices of the blood of patients with ischaemic heart disease and of their relatives. In young normal individuals, whose family history is hereditary teinted with ischaemic heart disease, the level of total lipids, cholesterol, cholesterol of beta-lipoproteids, beta-lipoproteids and non-estherified fatty acids was statistically significantly higher than in the control group. In the older age groups, however, this difference becomes insignificant. The blood level of cholesterol and beta-lipoproteids is determined by genetic factors to a higher degree than the level of total lipids. The introduction of a correction factor into the correlation analysis of the above biochemical parameters indicates the changes developing with age in the proportional role of the environmental and genetic factors in the lipid metabolism disorders, the importance of the environmental factors progressively growing.