Luteinizing hormone releasing hormone (LHRH), 100 µg, was administered to 60 patients with secondary amenorrhea. No side effects or adverse reactions occurred. Delayed FSH and LH peak outputs were observed in patients receiving LHRH subcutaeously rather than intravenously, but responses were otherwise comparable. The majority of patients with secondary amenorrhea had responses which fell into the 95% confidence limits of responses for normal ovulating women. Responses of patients with different forms of dysfunction may be similar, and patients with similar pathology may respond quite differently. The LHRH stimulation test may assist in the diagnosis of particular hypothalamic, pituitary, or gonadal dysfunction, but it must be used clinically in the context of a carefully integrated study.