SUMMARYThe effect of synthetic LHRH on plasma concentrations of LH, FSH, testosterone and testosterone response to i.v. HCG was studied in fifteen normal men and in fifteen men with impotence.The mean basal concentrations of LH, FSH and testosterone in the men with impotence were not significantly different from those of the normal group. A normal response of gonadotrophins and testosterone was also observed. It is concluded that a normal pituitary sensitivity to synthetic LHRH and a normal response to endogenous and exogenous gonadotrophins exist in this particular disorder.