59 heterozygous and 6 homozygous patients with familial hyperchole sterolemia were screened for atherosclerosis of the aortic root and cardiac valves by echocardiography. Pathological echocardiographic changes were found in 59% of heterozygotes and in all homozygotes. In heterozygotes, aortic root sclerosis usually appears after the age of 30 and its frequency increases progressively with age. Homozygotes showed severe changes before the age of 10. In heterozygotes, a pathological echocardiogram correlated strongly with the presence of overt coronary heart disease. Echocardiography proved to be a useful non-invasive method for better evaluation of the individual coronary risk in patients with familial hypercholesterolemia.