Abstract Study Objective This study was undertaken to assess the causes and treatments of menorrhagia in adolescents hospitalized for this menstrual disorder. Design A retrospective chart review was performed of all adolescents ≤20 years of age with menorrhagia adnlitted at the University of Michigan from 1979 to 1995. Information regarding medical history, hematologic parameters, treatment, and diagnosis was extracted from each chart. Pregnant and premenarchal patients were excluded. Results Thirty-seven adolescents with 46 admissions for menorrhagia were identified. The average age of menarche was 12.9 years and the average age at admission was 15.9 years. Nineteen adolescents had significant medical diseases. For the 46 admissions, causes of menorrhagia were anovulation (21), hematologic disease (15), chemotherapy-related (5), and infections (5). Transfusions of blood products were performed in 28 of the admissions. Treatments included oral contraceptive pills or progestins (30), intravenous conjugated estrogens (8), antibiotics (4), immune gammaglobulin (3), DDAVP (3), and prednisone (1). Twelve surgical procedures were performed, including eight dilatation and curettages (D&Cs), three laparoscopies, and one hysterectomy. Conclusions Sixty-one percent of admissions for adolescent menorrhagia were in adolescents with significant medical problems. The patients with menorrhagia who required admission had severe anemia and were transfused in 63% of cases. The predominant causes for these admissions included anovulation in 46%hematologic disease in 33%chemotherapy in 11%, and infection in 11%. Hormonal regulation or suppression of menses should be considered in adolescents with significant medical disease.