In patients with various forms of ischemic heart disease the following indices were examined by radial immunodiffusion: alpha-1-acid glycoprotein, alpha-1-antitrypsin, haptoglobin, alpha-2-glycoprotein, beta-2-glycoprotein, immunoglobulin, C3 and C4 complement fractions. The changes in the serum glycoproteins during the acute phase of myocardial infarction are pointed out. The changes in the immunoglobulins and the complement fractions in patients with ischemic heart disease are discussed. Their determination in patients with stenocardia and past myocardial infarction is of no diagnostic value.