To determine the incidence and pathophysiology of erectile dysfunction (ED) in patients with aortoiliac occlusive disease (AIOD) and the effects of aortofemoral surgery, including endarterectomy (E) and reconstruction (R), on erectile function (EF). Evaluation of EF before and 3 months after surgery. 31 out of 40 male patients scheduled for aortofemoral surgery were given multiple choice questionnaires and penile dynamic Colour Doppler Ultrasonography. Of the 31 who agreed to enter the study five (16%) were found to be potent and 26 (84%) to suffer from ED. This was purely arteriogenic in 8% of the cases, purely venogenic in 23%, combined arteriogenic and venogenic in 53%, and neurogenic in 16%. Twenty patients returned for postoperative evaluation of EF, nine who had undergone E and 11 who had undergone R. Improvement of EF, in terms of increased penile arterial inflow, occurred in seven patients, six who had undergone E and one who had undergone R. EF remained unchanged in nine patients, three who had undergone E and six who had undergone R. Deterioration of EF occurred in four patients, all who had undergone R, and was attributable to decreased arterial inflow in two cases and to neurogenic surgical injury in the other two. The majority of patients with AIOD suffers from ED. Reduced penile arterial inflow and cavernovenous leakage are equally important in the pathophysiology of ED in patients with AIOD, suggesting that atherosclerosis may also compromise the penile veno-occlusive mechanism. Endarterectomy seems more likely than reconstruction to improve or maintain EF.