The physiological and pathophysiological basis of hypothalamic amenorrhoea are reviewed as well as the clinical results of chronic intermittent (pulsatile) administration of Gn-RH in the treatment of infertility. Hypothalamic amenorrhoea is considered to be the result of a deficient hypothalamic secretion of Gn-RH. By pulsatile administration of Gn-RH, which is a pre-requisite of normal pituitary gonadotrophic function, deficient endogenous Gn-RH is replaced. If an adequate dose of Gn-RH is provided, which takes into account the degree of impairment of hypothalamic function in the individual case, follicular maturation, ovulation and corpus luteum formation are achieved in nearly every treatment cycle. Although dependent also on factors other than the treated dysfunction, a high conception rate is achieved.