A 10-year-old boy with idiopathic epilepsy refractory to treatment from age 4 and with clinical signs of hyperandrogenism was treated with chlormadinone acetate (24 mg/day) during two alternate periods of 3 months. The administration of chlormadinone was associated with a marked clinical and electroencephalographic improvement as well as a concomitant decrease in the levels of plasma testosterone and delta4 androstenedione. No changes in plasma gonadotropins were observed. Placebo had no effect neither in seizures nor in the concentration of hormones in the plasma. Since chlormadinone acetate is not a very potent gonadotropin inhibitor in males, it is suggested that the clinical and electroencephalographic improvement associated with the use of this compound, might be the consequence of a decrease in the plasma levels of androgens, mainly testosterone.