Fifty patients with severe aplastic anemia had no transfusions of blood products until just before marrow transplantation from HLA-identical family members. Of the 50, 42 are still alive 1 to 12 years after transplantation (median, 7 years). By actuarial standards, the 10-year probability of survival is 82%. Of the 42 surviving patients, 37 have Karnofsky performance status scores of 100% and 5 with chronic graft-versus-host disease have scores ranging from 50% to 90% (median, 80%). The 8 deaths were caused by early infection in 1, graft rejection in 1, acute graft-versus-host disease in 3, and chronic graft-versus-host disease in 3. All deaths occurred within two years after transplantation. The incidence of graft failure was 10%. Acute graft-versus-host disease developed in 14 of 44 patients at risk and chronic graft-versus-host disease, in 15 of 41. Risk factors for development of chronic graft-versus-host disease included increased age (p = 0.008) and presence of acute graft-versus-host disease (p = 0.001). The only factor associated with increased risk of death was development of acute graft-versus-host disease (p = 0.05). Results of this study extend our previous finding that patients with severe aplastic anemia who have transplants before the onset of transfusion-induced sensitization have an excellent probability of long-term survival and a normal life.