Six children with myelodysplastic syndrome underwent allogeneic bone marrow transplantation (BMT) from their HLA-identical siblings. Ages ranged from six to 16 years. French-American British (FAB) diagnosis was refractory anemia with excess blasts (RAEB) in three, RAEB in transformation (RAEB-t) in one and chronic myelomonocytic leukemia (CMML) in two cases. Two patients had progressed to leukemia before BMT. All patients received busulfan and cyclophosphamide as a conditioning regimen. Antithymocyte globulin (ATG) was administered to two of them due to the multiple transfusion history. Graft versus host disease (GVHD) prophylaxis consisted of cyclosporine-methotrexate. Engraftment was documented in all patients except one who underwent a second infusion of bone marrow cells. She died in the early post-transplant period with pancytopenia and veno-occlusive disease of the liver. Two patients died from disease recurrence. Three patients are alive >12 months post-transplant, two are in remission and one just relapsed at +16 months and is now being prepared for a second bone marrow transplant. The only significant factor for favorable outcome was short duration between diagnosis to transplant in the two patients in remission.