Fertility outcomes in hypopituitaric women are about half of those reported in isolated hypogonadotropic hypogonadism; GH deficiency (GHD) is a major contributor to poor pregnancy rate. GH seems to play a physiological role in the control of male sexual maturation and adult reproductive functions. In males, GH regulates gonadal differentiation, steroidogenesis, and gametogenesis, as well as gonadotropin secretion and responsiveness. In females, GH has a role not only as a modulator on gonadotropins, mediated by the property of IGF-I to amplify the action of both LH and FSH on granulosa, but also, through a direct GH action, on follicular maturation. GH treatment seems to play an important role in the sensibilization of ovary responsivity and uterine morpholgy in GHD patients. Since GH, directly or indirectly via IGF-I, regulates reproductive functions at all levels of the hyophyseal-pituitary-gonadal, it should always be tested as a possible cause of unexplained infertility.