A ratio cholesterol esters/apo B in very low and low density lipoproteins (VLDL and LDL), characterizing their cholesterol-transport function, as well as a ratio cholesterol esters/apo A-I in high density lipoproteins (HDL) HDL2 and HDL3, demonstrating the loading of cholesterol per unit of their main protein, were studied in 16 patients with ischemic heart disease accompanied by coronary atherosclerosis documented by angiography and in 36 healthy men. In patients with coronary atherosclerosis and low level of HDL cholesterol, particles of atherogenic lipoproteins were overloaded with cholesterol esters, while the ratio cholesterol esters/apo A-I was decreased in HDL2 and HDL3 as compared with controls. These alterations might be related to an increase in efficiency of cholesterol esters transport from HDL into VLDL and LDL as a result of dissimilar transformations in chemical and structural characteristics of surface monolayer of VLDL and HDL particles studied earlier.