Allogeneic bone marrow transplantation (BMT) is potentially curative therapy for leukemia, lymphoma, and marrow failure. Ninety-two patients have received allogeneic BMT at Oklahoma Memorial Hospital in the past 10 years. Patients with acute myelogenous leukemia (AML; N = 30), chronic myelogenous leukemia (CML; N = 27), acute lymphoblastic leukemia (ALL; N = 12), myelodysplastic syndromes (MDS; N = 8), lymphomas (N = 8), and aplastic anemia (N = 7) were treated with a variety of myeloablative preparative regimens. The major causes of mortality were bacterial, viral, and fungal infections, or disease relapse. Standard and high risk (refractory or multiply-relapsed disease) AML, CML, and ALL patients had median survivals of 14.5 months vs. 3 months, > 18 months vs. 9 months, and 10 months vs. 4.5 months (p = 0.01), respectively. At 7.5 years median follow-up, 71% of the aplastic anemia patients are disease-free. Guidelines for the optimal time for BMT have been developed that encourage transplantation earlier in the course of the disease, thus facilitating better outcomes with these otherwise fatal disorders.