In an attempt to clarify the etiology of amenorrhea, some amenorrhea patients were examined for steroid hormone in urine and serum LH-RH tests. LH-RH tests revealed that first grade amenorrhea cases tended to show LH hyper-reactions and FSH normal reactions, while second grade amenorrhea cases showed either insufficient reactions or hyper-reactions to both LH and FSH. The measurement of estradiol and progesterone in the blood revealed no significant differences between two grades. Concerning first grade amenorrhea, based on the measurements of steroid hormones in the urine, 17-hydroxylase and desmolase activities were significantly high before the administration of dexamethasone, and after the administration, the activities and reaction to HCG stimuli were normal. These results indicated that these enzymes act immoderately and, therefore, influence the ovary functions. Concerning second grade amenorrhea, one out of the three patients had insufficient reactions to LH-RH tests and showed the same tendency as the first grade amenorrhea cases in regard to 17-hydroxylase and desmolase. The other two patients which had FSH hyper-reactions, however, showed normal though rather low values of 17-hydroxylase and desmolase activities even before dexamethasone administration. This tendency was further intensified by administration of dexamethasones with the reactions of these entymes to HCG becoming low, which indicates insufficiency in the ovarian hormone system, not the effects of the adrenal system. In terms of 11-hydroxylase and 21-hydroxylase activities, the second grade amenorrhea case reacting insufficiently to LH-RH tests differed from first grade amenorrhea cases and were the same as the other two cases of second grade amenorrhea. This result implies that, in order to find disorders which cannot be detected LH-RH tests or by the measurements of steroids in the blood, the measurements of steroids in the urine are needed.