OBJECTIVES: The objectives of this study were to assess (1) whether treatment with oral contraceptives, in comparison with medroxyprogesterone and placebo, improved bone mineral in women with hypothalamic amenorrhea and (2) whether treatment with medroxyprogesterone, in comparison with placebo, improved bone mineral in women with hypothalamic oligomenorrhea. STUDY DESIGN: The study was a randomized, controlled clinical trial. Twenty-four white women, aged 14 to 28 years, with hypothalamic amenorrhea or oligomenorrhea were prospectively enrolled for a 12-month intervention period. Amenorrheic subjects were randomized to receive oral contraceptives, medroxyprogesterone, or placebo. Oligomenorrheic subjects were randomized to receive medroxyprogesterone or placebo. Bone mineral was measured by dual-energy x-ray absorptiometry at baseline and at 6 and 12 months. RESULTS: In amenorrheic subjects spine and total body bone mineral measurements at 12 months were greater in the oral contraceptive group than in the medroxyprogesterone and placebo groups when baseline bone mineral measurements, body weight, and age were controlled for (p