The total and alpha-cholesterol content, as well as the triglyceride concentration were determined in 184 patients, suffering from diabetes mellitus of the I and II types, with or without ischemic heart disease (IHD) and in 96 persons with the disordered glucose tolerance test. It was stated that the alpha-cholesterol level in diabetics with the II type of the disease is lower than that in the controls and patients with the I type of diabetes mellitus. In males and females with the II type of diabetes mellitus the alpha-cholesterol level is lower than that of the controls. In males with the I type of the disease its concentration is higher and in females is the same as in the controls. In the presence of IHD the alpha-cholesterol level is lower comparatively to that of the controls (males and females) with diabetes mellitus of the II type and in females with the I type. In males with the II diabetes type and IHD the alpha-cholesterol level is lower than that of the males with the I type and IHD. In females there are no significant differences. The difference in the alpha-cholesterol content, depending on the patient's sex, is seen only in persons with diabetes mellitus of the II type, aged 45 to 65 years, and in patients with the I type, aged 30 to 45 years. Sex differences in the triglyceride content of patients with diabetes mellitus of thek I and II types mere not observed, their level being higher than that of the controls.