The authors describe the first successful bone marrow transplant for the treatment of hemoglobinopathy Olmsted in a boy who presented with severe transfusion-dependent hemolytic anemia and jaundice at age 4 months. He received bone marrow from an HLA-identical sibling with normal hemoglobin electrophoresis after conditioning with busulfan, cyclophosphamide, and antithymocyte globulin when he was 18 months old. The posttransplant course was uneventful. Two years after transplantation the patient has a normal hemoglobin level without evidence of hemolysis. DNA analysis shows 100% chimerism of donor cell origin, confirming full engraftment with normal hematopoietic cells.