The clinical history and physical examination remain the most important factors in determining the presence, anatomic location, and physiologic extent of arterial occlusive disease and the need for operation. The physician should refrain from ordering arteriography to confirm the diagnosis of arterial disease unless operation is warranted. If peripheral arterial occlusive disease is diagnosed clinically, its anatomic and physiologic extent can be determined qualitatively and quantitatively by Doppler ultrasonic studies. These studies are also useful in following the natural history of or the influence of therapy on the course of arterial occlusive disease. Ultrasonic studies coupled with careful clinical assessment and with arteriographic evaluation prior to planned operation provide an optimal armamentarium for the diagnosis and management of peripheral arterial occlusive disease.