A case of hypothalamic-pituitary failure is reported. A 28-year-old man who had been treated with testosterone for hypogonadism for two years was admitted to our hospital with the chief complaint of sexual problems. The serum level of gonadotropins was very low and hypophysial responses to luteinizing hormone-releasing hormone (LH-RH) were good. Treatment was started with subcutaneous pulses of 10 micrograms LH-RH every 120 minutes using a portable infusion pump. Gradually, his potency improved and ejaculation returned. The serum concentration of FSH, LH and testosterone increased to the normal range of adult males and the testicular volume increased rapidly from 5 ml to 14 ml after 13 weeks of treatment. Sperms appeared in the ejaculated fluid after 25 weeks and, after following 16 weeks, the concentration of sperms increased up to 20 x 10(6)/ml. Prolonged pulsatile subcutaneous administration of a low-dose of LH-RH at a physiologic frequency was an effective therapy for pubertal induction and maturation in hypogonadotropic hypogonadism due to hypothalamic-pituitary failure.