The diagnosis of premature ovarian failure was made in 35 women (ages 17 to 40) with increased concentrations of follicle-stimulating hormone and luteinizing hormone. Three had primary amenorrhea, 29 had secondary amenorrhea (less than one to 15 years), and three had irregular menstrual intervals of less than six months. Symptoms and signs of estrogen deficiency were present in fewer than 50% of these women and were not helpful in distinguishing the different causes of ovarian failure. Six of these women had an autoimmune disorder associated with ovarian failure. Thirteen of 16 women had a normal 46,XX karyotype, and five of 14 women who had an ovarian biopsy had a specimen that contained follicles with oocytes. Two women conceived after they developed ovarian failure and while taking cyclic estrogen and progestin.