A significant difference in bilateral systolic brachial artery pressures and the presence of systolic bruit over a subclavian artery suggests occlusive disease in the innominate or subclavian arteries. Two thousand patients with these signs underwent ultrasonography of the carotid, subclavian, and brachial arteries in our laboratory. Doppler recordings of a vertebral artery, with hyperemia testing of the ipsilateral arm, identified those with a subclavian steal syndrome. In each case, angiography confirmed the laboratory diagnosis. The effectiveness of corrective surgery was evaluated noninvasively. Illustrative cases are presented and discussed.