Peripheral arterial disease is a common but underdiagnosed and undertreated disorder with substantial morbidity and mortality. The pathophysiology of peripheral arterial disease and the risk factors for developing it are similar to those for atherosclerotic disease occurring at other sites. Peripheral arterial disease can be diagnosed accurately with simple, noninvasive, office-based tests that measure the severity of the disease and provide valuable prognostic information. Optimal medical therapy includes a supervised exercise program, tobacco cessation, and modification of treatable risk factors. Cilostazol can improve pain-free and peak walking distances in patients with intermittent claudication. As a general rule, patients with lifestyle-limiting claudication who do not respond to medical management or those with critical limb ischemia should be referred to a vascular specialist for consideration of revascularization.