A retrospective review was done of the results of the combined intracavernous injection and stimulation test, an office based functional test for impotence. In this procedure the quality of erection is assessed 15 minutes after injection of a vasoactive drug. In our series 90 patients did not achieve full rigidity and were instructed to perform genital self-stimulation for 5 minutes before reevaluation. Of the 90 patients 67 (74%) improved with stimulation and 23 (26%) showed no improvement. At 5 minutes after stimulation a decrease in the quality of the erection was found in 25 patients--a finding suggestive of venogenic impotence. When cavernosometry and cavernosography were performed 21 patients (84%) had moderate to severe venous leakage and 4 (16%) showed none. Self-stimulation after diagnostic injection of intracavernous agents can improve patient response, and may better predict the potential success of a therapeutic self-injection program and the diagnosis of suspected venogenic impotence.