A 33-year-old male with refractory relapsed central nervous system lymphoma underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) from an HLA-identical sibling after reduced-intensity conditioning chemotherapy. The preparative regimen for allo-HSCT consisted of fludarabine and busulfan. Cyclosporine (CsA) and short-term methotrexate were used as prophylaxis for acute graft-versus-host disease (GVHD). Although CsA was quickly reduced to induce a graft-versus-lymphoma (GVL) effect, no symptoms of GVHD and GVL effect were evident. Donor lymphocyte infusion (DLI) was performed on day +40 following transplantation. The patient developed acute GVHD (grade III) after DLI, and lymphoma regression was observed after the occurrence of GVHD. Four months after transplantation, complete remission was achieved with extensive chronic GVHD, and the patient continues to be disease free at 15 months after transplantation.