Two-Hundred consecutive patients complaining of impotence have had complete urological and neurophysiological investigations to determine a possible organic cause of their sexual dysfunction. All patients had urological and neurological history and examination: nocturnal penile plethysmography, papaverine intracavernosus injection, penile arterial doppler and/or arteriography, cavernography-cavernometry, serum hormonal levels, and bulbocavernosus reflex (BCR). Peripheral conduction velocities and pudendal-evoked responses (PER) were also performed if neurological history or examination and/or BCR were abnormal. Only 30 patients (15%) had an abnormal BCR. In 17 patients, a neurological associated disorder was found. Four patients had normal erections during plethysmography, despite their complaints. Nine patients with an isolated prolonged BCR also presented a vascular abnormality that could explain impotence. Abnormal PER was observed only in 6 patients, 4 of them with a prolonged BCR as well. These results suggest that PER is not an interesting neurophysiological routine test for the diagnosis of neurogenic impotence and that the relationship between an abnormal BCR and neurogenic impotence is doubtful.