Correlation between ovarian follicular apparatus and hormonal parameters such as serum gonadotropin and urinary estrogen levels was investigated in patients with primary and secondary amenorrhea. Serum gonadotropin levels were elevated in amenorrheic patients without ovarian follicles or with follicles of low developmental stage and pituitary responsiveness to LH-RH in these patients were marked compared with patients with follicles of high developmental stage or normal ovulating women in the follicular phase of the menstrual cycle. The 24-hour urinary excretion of total estrogens was low in patients without follicles or with follicles of low developmental stage and ovarian responsiveness to exogenous gonadotropins was quite low in comparison with patients with highly developed follicles or normal control subjects. Thus, serum gonadotropin and urinary estrogen measurements and LH-RH and gonadotropin loading tests are diagnostic of the presence or absence and the state of development of ovarian follicles in the diagnosis and treatment of primary and secondary amenorrhea.