Peripheral arterial diseases are common problems because atherosclerosis, the most common cause of both occlusive peripheral arterial disease and aneurysmal disease, is a feature of an aging population. The less common types of occlusive peripheral arterial disease--the vasospastic disorders and the arteritides--although frequently not addressed to any extent in medical school curricula or in residency programs in family and internal medicine, offer the alert and informed clinician diagnostic and therapeutic opportunities that are too important to neglect. As a group, abnormalities of the peripheral arteries are easy to detect if careful observation and examination of the extremities is included in the physical examination and attention to functional disorders is included in the medical history. In this presentation, the clinical features, physical findings, complications, useful noninvasive diagnostic tests, imaging techniques, and therapeutic options for atherosclerotic occlusive peripheral arterial disease (both chronic and acute), uncommon types of occlusive arterial disease of both the lower and upper extremities, the vasospastic disorders, and the peripheral arterial presentations of the arteritides are reviewed. The application of natural history and comorbidity of a particular arterial disease, when available, is emphasized in the formulation of management for the individual patient.