Peripheral arterial disease, which is caused by atherosclerotic stenosis or occlusion of the leg arteries, is an important manifestation of systemic atherosclerosis. The age-adjusted prevalence of symptomatic and asymptomatic peripheral arterial disease is approximately 12% in the general population. The overall prevalence and incidence of the disease is likely to increase with the aging of the population. Peripheral arterial disease is a relatively benign condition in terms of local disease. Five years after the diagnosis, 75% of the patients remain clinically stable. On the contrary, life expectancy, even in the absence of any history of myocardial infarction or ischemic stroke, has decreased by 10 years. These patients have approximately the same relative risk of death from cardiovascular causes as do patients with history of coronary or cerebrovascular disease. Moreover, the severity of peripheral arterial disease is closely associated with the risk of myocardial infarction and death from vascular disease. The lower the ankle-brachial index, the greater the risk of cardiovascular events. Furthermore, peripheral arterial disease is a significant independent predictor for cardiovascular mortality also in coronary patients. The risk factors associated with peripheral arterial disease are essentially the same as for coronary heart disease: older age, cigarette smoking, diabetes mellitus, hypertension, and hyperlipidemia. The excess morbidity and mortality for cardiovascular disease in these patients has not been fully explained. Patients with peripheral arterial disease show a systemic endothelial dysfunction and an increase in the serum concentration of activated white blood cells, endothelin, and C-reactive protein that may trigger acute coronary syndromes. In peripheral arterial disease the functional status is often severely impaired. Peak exercise performance has decreased to about 50% of that of age-matched controls, equivalent to moderate-severe heart failure. Epidemiological studies support the concept that patients affected by peripheral arterial disease, without established coronary heart disease, have a coronary heart disease high risk equivalent. In spite of this, peripheral arterial disease remains an underdiagnosed and undertreated disease. As the role of cardiologists is expanding, the purpose of this review was to awaken the clinician to the significance of lower limb atherosclerotic occlusive diseases.