Sixty-two patients (31 males, 31 females) with familial hypercholesterolemia (FH) underwent a vascular examination by Doppler ultrasound. The ankle/arm systolic pressure index was determined, and serum lipoproteins were analyzed. Eight of 124 legs examined (6.5%) showed an ankle/arm pressure index less than 0.95, suggesting flow reducing stenosis. Common carotid, internal carotid, and iliac arteries were evaluated by echo Doppler examination with spectral analysis. Forty-five of the 372 arteries examined (12.1%) had detectable abnormalities at echo Doppler examination. Iliac and internal carotid artery lesions were significantly (P less than 0.01) more frequent among FH patients than in a control group (30 men, 20 women) comparable for sex and age. The mean age of the patients with heterozygous FH and detectable arterial lesions was 45.3 years and that of those without lesions 30.7 years (P less than 0.05). When 14 patients with heterozygous FH and arterial lesions were compared to another 14 without lesions and matched for age and gender, it was found that patients with lesions had on average lower concentrations of HDL-cholesterol, and that 10 of 14 cases were actual smokers.