A successful case of pulsatile GnRH treatment of a 31 years old male with hypogonadotropic hypogonadism is described. During therapy for six months the secretions of LH, FSH and testosterone were normalised and the testicular volume increased to normal adult size. The sperm count increased from 0.0 to 0.9 mill/ml. Subsequently the sexual partner became pregnant and delivered a normal female infant.