Content of apo A-I constitute 136 mg/100 ml, of apo A-II--64 mg/100 ml and of apo E--10 mg/100 ml in blood plasma of 20--60 years old men with normal concentration of cholesterol (alpha-CS) in blood. In the patients with hyper-alpha-lipoproteinemia (alpha-CS was above 76 mg per 100 ml) concentrations of apo A-I and apo A-II were distinctly higher (173 and 71 mg per 100 ml, respectively) and that of apo E--was lower (8 mg per 100 ml) as compared with the healthy persons. Under the conditions of hypo-alpha-lipoproteinemia (alpha-CS was below 37 mg per 100 ml) the contents of apo A-I and apo A-II were decreased down to 116 and 50 mg per 100 ml, respectively, and that of apo E--increased up to 12 mg per 100 ml. Concentration of the total fraction of high density lipoproteins (LPHD), LPHD2 and their subfraction LPHD2a and LPHD2b was also distinctly increased in hyper-alpha-lipoproteinemia; it was decreased in hypo-alpha-lipoproteinemia, while the LPHD3 content was slightly altered in blood plasma. The capacity of LPHD to transfer of CS appears to increase in hyper-alpha-lipoproteinemia and to decrease in hypo-alpha-lipoproteinemia. As shown by correlation analysis, metabolism of LPHD3 occurred independently from the other LPHD subfractions.