The case of a 32-year-old female with relapsed myelodysplastic syndrome (MDS) after second course of allogeneic transplantation is described. The peripheral blood stem cell transplantation was performed as early as 3 months after the initial bone marrow transplantation because of rejection and relapse; however, the patient again relapsed 2 months later. Immediate discontinuation of cyclosporine resulted in the progression of pancytopenia and the development of high fever, liver dysfunction and skin eruption. The patient was then treated with dexamethasone, which successfully stabilized these symptoms. After these clinical events, a dramatic hematological response was obtained; the blast rate was reduced from 10.6 to 0% in bone marrow aspiration, and pancytopenia was restored to normal levels. Moreover, fluorescence in situ hybridization analyses with X and Y chromosome-specific probes revealed that hematopoietic precursor cells were predominantly of donor origin. The patient subsequently received donor lymphocyte infusion (DLI) from the original donor. Currently, 2 years after DLI, the patient continues to be in remission.