To delineate neural, arterial, and venous components contributing to impotence, we used a previously described noninvasive screening sequence combined with stimulation of artificial erection with papaverine injection, selective pudendal arteriography (SPA), and dynamic cavernosography (DC). Among 572 men with impotence, age range 17 to 78 years (average age 54.8 years), 26 men with potential cavernosal leaks in absence of other factors were identified; 16 underwent DC; among these five had normal cavernous venous drainage. Eight men with abnormal cavernosal venous drainage required cavernous infusion flow rates higher than 120 ml/min to obtain erection and higher than 40 ml/min to maintain erection. Radiographic studies showed cavernosal leakage in all eight patients. Eight men, ages 39 to 61 years, underwent surgical ablation of abnormal cavernosal venous drainage. Among these, five men have had excellent results for up to 3 years. One failure was related to unrecognized penile arterial disease later shown by SPA. In two men small doses of papaverine now induce erection. We now recommend SPA before DC to rule out an arterial abnormality. Accurate identification of factors contributing to erectile failure is critical for successful treatment; in this experience candidates for correction of cavernosal leak syndrome were uncommon.