Pulsatile administration of gonadotrophin releasing hormone (GnRH) is a very effective treatment for induction of ovulation in hypothalamic amenorrhoea (HA). Thirty-seven women have been treated for a total of 117 cycles which resulted in 42 pregnancies--four treatment failures occurred. If these cycles are excluded, the 42 pregnancies were obtained within 2.3 cycles. One twin pregnancy occurred and no hyperstimulation was observed. The treatment was administered intravenously with a dosage schedule based on the grading of HA. We concluded that pulsatile GnRH was safe and very successful in induction of pregnancy in HA. Other indications (polycystic ovary syndrome and luteal phase defect) remain much less suitable for this treatment.