We investigated the intracavernous pressure decay(phase II of dynamic infusion cavernosometry and cavernosography: DICC) before and during perineal muscle stimulation by vibration in 27 patients of erectile dysfunction. The Causes of erectile dysfunction were psychogenic in 6 cases and vasculogenic in 21 cases(11 venogenic, 2 arteriogenic and 7 combined). In the psychogenic erectile dysfunction, the pressure decay(mmHg/30 sec) was 30.67+/-9.38 (Mean+/-S.D.) before perineal stimulation and 25.83+/-15.03 during perineal stimulation: there was no statistically significant difference. In the venogenic erectile dysfunction, the pressure decay before and during stimulation were 79.73+/-26.17 and 67.89+/-34.48, which showed very significant difference(P<0.001). In the combined arteriogenic and venogenic erectile dysfunction, the pressure decay before and during stimulation were 93.63+/-20.98 and 88.63+/-16.29, which showed significant difference(P<0.01). There was no significant difference in pressure decay before and during stimulation in the arteriogenic erectile dysfunction. Therefore, perineal muscle contraction seems to influence the intracavernous pressure and play an important role to prevent venous leak.