Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disorder (EBV-PTLD) is a complication of hematopoietic stem cell transplantation (HSCT). Standard initial treatment of patients with EBV-PTLD includes administration of rituximab or dose reduction of a calcineurin inhibitor. We report successful chemotherapeutic treatment of rituximab-resistant EBV-PTLD after HSCT in a patient with severe aplastic anemia (AA). A 38-year-old woman with antithymocyte globulin (ATG)-resistant severe AA received bone marrow transplantation from an unrelated donor (human leukocyte antigen-DR single-locus mismatch). The conditioning regimen included fludarabine, cyclophosphamide, ATG, and total body irradiation, and prophylaxis for graft-versus-host disease consisted of short methotrexate and tacrolimus. Neutrophil engraftment occurred on day 21. Left cervical lymph node swelling was observed after day 45, and analysis of a biopsy specimen revealed EBV-PTLD and a high blood EBV load (56,000 copies). The patient was treated with rituximab 4 times per week, but the lymphadenopathy continued and the blood EBV load increased to 96,000 copies. Half-dose treatment with rituximab, cyclophosphamide, vincristine, doxorubicin, and prednisolone (R-CHOP) was initiated on day 71. After 32 days of treatment with R-CHOP, the patient's neutrophil level was restored to > 0.5 × 10⁹/L and both the lymphadenopathy and the blood EBV load (< 100 copies) were rapidly reduced. Although chemotherapy is not preferred soon after HSCT, it may be an effective strategy for treating patients with rituximab-resistant EBV-PTLD. [J Clin Exp Hematop 54(2) : 149-153, 2014]