An 11-year-old boy with multiply relapsed lymphoblastic disease became transfusion dependent with myelodysplasia and chromosomal abnormalities after 5 years of aggressive therapy. At 5 years of age, he presented with transient idiopathic hypoplastic anemia and neutropenia that spontaneously resolved within a month. Three months later, he experienced lymphoblastic lymphoma in the left parotid region and subsequently experienced disease relapse in his testicles, bone marrow, and central nervous system during a 3-year period. He has received multiagent chemotherapy, autologous peripheral blood stem-cell transplantation, and testicular and whole neuraxis irradiation therapy. After craniospinal irradiation, he did not recover normal bone marrow function. His bone marrow was hypocellular, and he required platelet and erythrocyte transfusions and granulocyte colony-stimulating factor. Marrow cytogenetic studies revealed new multiple translocations. Within a month of the initiation of intravenous amifostine at 200 mg/m2/dose three times a week, his leukocyte count, neutrophil count, and hemoglobin level normalized. His platelet count also improved sufficiently to achieve transfusion independence. He has returned to school and engages in other normal activities for his age. Amifostine may improve hematopoiesis in secondary myelodysplastic syndromes in children.