A total of 132 consecutive patients with erectile impotence underwent extensive evaluation, including vascular evaluation with intracavernous injection of papaverine and penile duplex ultrasonography, to determine the etiology of impotence. Three vascular risk factors, smoking, diabetes mellitus and hypertension, were investigated for their impact on vasculogenic impotence. The patients were divided into four groups: one with no risk factors, one with one vascular risk factor, one with two vascular risk factors, and one with all three risk factors. The results of penile vascular evaluation in these patient groups were compared. The incidence of penile vascular impairment was found to be higher in patients with one vascular risk factor than in those with none. The proportion of abnormal penile vascular findings significantly increased as the number of risk factors increased. These data confirm the important role of vascular risk factors, smoking, diabetes mellitus, and hypertension, in the pathogenesis of organic impotence.