Familial hypercholesterolemia, an inheritable metabolic disorder, is the most powerful risk factor for the accelerated atherosclerosis. Mean intima-media thickness of carotid arteries was determined with B-mode ultrasonography in 28 young patients with familial hypercholesterolemia and in 28 normolipemic subjects. Serum lipids, lipoprotein(a), glucose, coagulation and fibrinolytic parameters were determined. Mean intima-media thickness was significantly greater in patients with familial hypercholesterolemia than in controls (0.71±0.15 vs. 0.49±0.08 mm, p<0.0001). In all subjects together mean intima-media thickness was positively correlated with total cholesterol, low-density lipoprotein cholesterol, triglycerides, and systolic blood pressure. In patients with familial hypercholesterolemia mean intima-media thickness was positively correlated with age and systolic blood pressure, while in controls it was correlated with systolic blood pressure, body weight and height, triglycerides and tissue plasminogen activator antigen and it was greater in males than females. Multiple regression analysis identified the group of patients with familial hypercholesterolemia, higher triglycerides and age as the independent determinants of IMT in all subjects together, while in controls these determinants were sex, age and triglyceride level.