The natural history of peripheral arterial occlusive disease is discussed. Severe limb-threatening ischemia is the most serious consequence of chronic arterial occlusive disease. Severe ischemia and amputation can be considered as an endpoint in peripheral vascular disease. Severe limb ischemia is relatively uncommon in isolated aortoiliac disease and this is more than twice in patients with either femoropopliteal or multisegmental disease. Subsequent studies have also demonstrated that both smoking and diabetes are associated with a substantial risk for sudden ischemia. A clear majority of about 50% deaths are caused by associated coronary artery disease, 15% to stroke and 10% to vascular disease in the abdomen. Ankle systolic blood pressure is one of the most significant factors in the progression of peripheral arterial occlusive disease and also for cardiovascular mortality. In the future, men need to know how therapies as exercise, during regimens would influence the most frequent complications besides severe limb ischemia, namely brain infarction and coronary artery disease.