The prognosis of patients suffering from peripheral arterial occlusive disease (PAD) is directly correlated with the severity of the disease. In critically ischemic legs, after one year only 50% will be alive with a preserved leg. The other 50% will die or undergo an amputation during this time. Reconstructive surgery is highly effective in PAD caused by extensive arterial lesions. Depending on the localization of the occlusion, operative procedures range from local desobliteration to profundoplasty and from aortofemoral to femorodistal bypass procedures. Especially in critical ischemia, time is of the essence for limb salvage. Evidence-based data for diagnosis and operative treatment are described in detail. Only the consequent use of these critical techniques can improve the prognosis of these patients.