Abstract: Fifteen day immature male rats were given by gastric garage gossypol acetic acid 30 mg/kg daily for 13 days. The production of testicular testosterone in vitro, both basal and hCG-stimulated, was reduced by 51% and 50% respectively, although the plasma testosterone level was not significantly reduced. The assay of LH/hCG receptors in testicular homogenate indicated that the binding of ¹²⁵I-hCG was reduced from 43.99±3.93% in the control to 25.01±2.08% in the gossypol group. It is suggested that gossypol acetic acid possesses inhibitory effects on both the secretory activity and LH/hCG receptor development of Leydig cells in immature rat testis.