Managing patients with peripheral arterial disease (PAD) requires an accurate assessment of the severity of the condition and the risk factors likely to predict disease progression. The spectrum of patient presentation ranges from asymptomatic to critical limb ischemia. Because about half of patients with PAD have coronary or cerebrovascular disease, the examination of presenting patients should be directed toward the entire cardiovascular system. The main diagnostic goal is to establish whether the symptoms are predominantly caused by PAD and to what degree the presenting problem is compounded by other comorbidities, such as diabetic neuropathy, arthritis, or venous disorders. The diagnostic process includes history taking, physical examination, noninvasive diagnostic testing, differential diagnosis, laboratory studies, and the use of the various imaging modalities, which in general are reserved for those PAD cases in which the clinician has already decided to intervene.