Forty patients with symptomatic aortoiliac and/or femoropopliteal occlusive arterial disease subjected to angiography were studied with duplex ultrasonography. The duplex scanning of the aortic, iliac, femoral and popliteal segments had a sensitivity of 93% in detecting significant stenoses and a specificity of 91%. The positive and negative predictive values were 75% and 98%, respectively. The sensitivity was relatively low in low-flow segments distal to total occlusions especially in patients with severe iliac disease and multiple distal femoropopliteal lesions. The results demonstrate the reliability of duplex scanning in detecting aortoiliac and femoropopliteal lesions.