In 77 patients with postinfarction cardiosclerosis the blood serum immunoglobulin level was studied along with some indices of the lipid and protein metabolism. An increased blood level of immunoglobulins A, M and G was observed in postinfarction cardiosclerosis cases, those with hyper-beta-lipoproteinemia, hypercholesterolemia and C-reactive protein having a significantly higher level of immunoglobulin G and than the rest of the patients. In those having an increased content of immunoglobulin G in the blood serum hypo-beta-globulinemia was observed, as well as a considerable increase of the gamma-globulin fraction as compared to those having a normal or decreased level of immunoglobulin G. Proceeding from these data the authors suggest the presence of autoimmune shifts in the patients with postinfarction cardiosclerosis that are closely connected with lipid and protein metabolism disorders.