Congenital adrenal hypoplasia (CAHP) in its X-linked form is associated with hypogonadotropic hypogonadism (HH). A 23 year old man with this disorder received substitution therapy with gluco- and mineralocorticoids starting one week after birth and, recently, pulsatile subcutaneous GnRH treatment via a miniature infusion pump with stepwise increasing doses from 50 to 200 ng/kg body weight/2 hours for a total of 394 days. Testosterone levels increased from prepubertal levels to 409 ng/dl after 2 weeks and to 626 ng/dl after 3 months of treatment. The results of pulsatile GnRH therapy in our patient prove the hypogonadotropic hypogonadism to be of hypothalamic origin. Pulsatile GnRH substitution is a successful therapeutic regimen in patients with CAHP leading to pituitary and gonadal maturation.