Chronic intermittent low dose LHRH therapy was given to 7 normoprolactinemic women with long-standing secondary amenorrhea, low-normal gonadotropin levels and low endogenous estrogen production (WHO group I). Four of them were involuntarily infertile. A portable, computerized infusion pump (Zyklomat, Ferring) delivered 20 .mu.g LHRH every 90 min through a chronic indwelling catheter inserted s.c. in the fat tissue of the lower abdominal wall. The LHRH administration was continued until menstruation or pregnancy. Nine treatment courses over 21-69 days were given. Twelve ovulatory cycles were induced by the pulsatile LHRH treatment. The corpus luteum function was normal in 7 cycles. Temporary interruptions of the pump function in 2 patients and hematomas at the catheter site in another 2 patients may have caused the luteal phase insufficiency. One of the 4 infertile women became pregnant. She developed ovarian hyperstimulation during her 1st treatment cycle. The ovarian enlargement regressed despite continued LHRH therapy and a 2nd ovulatory cycle was induced. Pulsatile administration of low doses of LHRH can induce follicular maturation, ovulation and normal corpus luteum function in hypo- or normogonadotrophic women with secondary amenorrhea with low endogenous estrogen production. The LHRH therapy can be given with the same pulse frequency throughout the induced cycle. Should pregnancy not occur the pulsatile LHRH treatment can be continued without interrruption to induce a 2nd ovulatory cycle.