Posttransplantation lymphoproliferative disorder (PTLD) is one of the well-recognized complications after allogeneic stem cell transplantation (SCT). It generally occurs early after SCT, and only a few reports of late-onset cases are available. We report a 58-year-old male patient who developed lymphoma 4 years after allogeneic SCT for chronic myeloid leukemia. The presence of c-myc translocation and Epstein-Barr virus-encoded RNA in the lymphoma cells, without rearrangement of the 3'-bcr region, confirmed the histopathologic diagnosis of Burkitt lymphoma. DNA chimerism analysis revealed that the lymphoma cells were of donor origin. The patient achieved complete response with intensive chemotherapy. To our knowledge, this is the first report of Burkitt lymphoma as a PTLD occurring after allogeneic SCT.