A series of 235 patients with infertility due to disturbances of ovulation were treated with human gonadotropins or with clomiphene citrate. The patients were divided into two main groups according to the level of urinary gonadotropins to the endogenous oestrogen activity. Patients with corpus luteum insufficiency formed a separate group. Group I (low urinary gonadotropins, no evidence of endogenous oestrogen activity) comprised 100 patients with primary, secondary, or postpartum amenorrhoea. Group II (gonadotropins in normal range, evidence of endogenous oestrogen activity) included 89 patients with secondary amenorrhoea, oligomenorrhoea, or anovulatory cycles. Forty-six patients with corpus luteum insufficiency formed group III.