The dorsal nerve of the penis is involved in sexual function. Until now, the nerve conduction velocity (NCV) of the dorsal nerve of the penis has been measured by dividing the distance between the stimulating and the recording electrodes by the latency to the negative peak of the action potential. With the penis stretched with a 1 lb weight, the NCV in normal men was 33 m/sec +/- 3.8. Measuring the NCV in this way, we became aware that when we decreased the distance between the stimulating and the recording electrodes, the velocity decreased. Furthermore these different measurements were linearly related. Taking this into account, we calculated the NCV with mathematical formula. In normal people, it turned out to be faster than reported previously.