To identify the effective dose of intravenous pulsatile gonadotropin-releasing hormone necessary to induce ovulation in patients with chronic anovulation of diverse etiology, 40 women were subdivided into four groups: idiopathic hypogonadotropic hypogonadism (IHH), functional hypothalamic amenorrhea, normoandrogenic oligomenorrhea, and polycystic ovarian syndrome (PCOS). During 90 treatment cycles, the dose was the only parameter that was progressively adjusted. The overall ovulation rate per cycle was 100% in IHH, functional hypothalamic amenorrhea, and normoandrogenic oligomenorrhea, using only 5 micrograms/90 minutes in functional hypothalamic amenorrhea and normoandrogenic oligomenorrhea and up to 7.5 micrograms/90 minutes in IHH. In PCOS, the ovulation rate was 67.6%, using up to 20 micrograms/90 minutes. The lesser degree of effectiveness observed in PCOS can probably be explained by the different basal endocrine profile presented by these subjects.