The function of the epididymis and of the sex accessory glands have been investigated in a selected group of varicocele patients with normal sperm count. In the seminal plasma of these patients free-L-carnitine, fructose and zinc levels were determined as functional markers respectively of epididymis, seminal vesicles and prostate. Despite the unvaried free-L-carnitine and fructose levels, zinc levels were significantly lower (p less than 0.001) than in the control group. The Zn/F ratio, an index of the ratio between the prostatic and vesicular secretions, resulted also lower (p less than 0.01) with respect to the controls. The authors suggest that the impaired prostatic function could arise from the decreased venous drainage in the vesico-prostatic plexus. In the same patients sperm motility resulted significantly lower than in the controls, and was positively related to zinc levels (r = 0.44, p less than 0.01) and, to a higher degree, to the Zn/F ratio (r = 0.62, p less than 0.001). Our data show that in this selected group of varicocele patients with a not yet altered tubular epididymal unit, sex accessory gland secretions can influence, per se, the motility of the ejaculated spermatozoa.