Nerve growth factor (NGF) is a potent neurotrophin signaling protein, the best-known member of a family of similar neurotrophins. Specific neuronal populations depends upon the neurotrophins for normal function and disturbances in NGF and neurotrophin supply have been implicated in neurodegenerative disease, diabetes, and hypertension. In this study, we measured peripheral and penile serum levels of NGF in 16 healthy potent controls. NGF was determined by sandwich ELISA method. On the average, the differences between peripheral and penile serum levels of NGF was 0.01 ng/ml (p>0.05), but there was a little variation between individual peripheral and penile serum was similar to those of NGF in penile serum. The peripheral serum levels of NGF in patients with diabetic neuropathy may be used to predict neurogenic impotence.