This study was designed to verify the validity of bulbocavernosus reflex latency(BCRL) and pudendal somatosensory evoked potential(SEP) in the evaluation of neurogenic erectile dysfunction and to lay out a scheme to uplift the diagnostic accuracy of BCRL and pudendal SEP. Eighty four subjects who were referred to Seoul National University Hospital EMG laboratory for the evaluation of the erectile dysfunction were examined. At first, history taking, physical examination, measurement of serum hormone level, rigiscan with audiovisual sexual stimulation were performed. In the next step, intracorporial papaverine injection, nocturnal penile tumescence test, BCRL and pudendal SEP were performed as indicated. Then the results of BCRL and pudendal SEP were compared to the final diagnosis obtained through additional studies. Psychogenic cause was most common and neurogenic, vascular, and hormonal causes followed. The diagnostic sensitivity of BCRL and pudendal SEP in the discrimination of neurogenic cases from nonneurogenic cases was 89.5% and 93.7%, respectively. The specificity was 89.7% and 64.7% in order. Among twenty seven subjects with abnormal BCRL or pudendal SEP, eight subjects were confirmed as psychogenic impotence at the final diagnosis. But psychogenic impotence was not found among nine subjects who had abnormal BCRL and pudendal SEP. Twenty three subjects with abnormal BCRL were divided into delayed latency group and no response group. Among thirteen subjects of delayed latency group, psychogenic cases were six and among ten subjects of no response group, psychogenic case was not found. In the evaluation of neurogenic impotence, BCRL was a sensitive and specific tool while pudendal SEP was sensitive but less specific. BCRL alone or pudendal SEP alone would be inadequate for the evaluation of neurogenic impotence, especially in discrimination with psychogenic one. To improve diagnostic accuracy in the evaluation of impotence, BCRL and pudendal SEP should be checked out all together. In the situation when only BCRL is available, it is recommendable to take unevokable bulbocavernosus reflex as meaningful.