Testosterone (T) and 5-a-Dihydrotestosterone (DHT) was measured in seminal plasma levels of forty-four varicocele patients and in seventeen normal men. T values were not significantly different from controls, while DHT values were significantly lower in varicocele patients. When grouped the patients according to the sperm count, we observed a decrease of DHT similar to that reported by other authors in oligozoospermic patients. However in the patients with normal sperm count, where the motility was the only parameter significantly lower, DHT in the ejaculate showed again a marked decrease. In contrast to that observed in the normal subjects, in the latter group, with normal sperm count, we observed a negative correlation between the age of the patients and DHT in the ejaculate. This suggests that the duration of varicocele per se could affect DHT seminal plasma levels.