We report herein a 21-year-old hepatitis B virus (HBV) female carrier who developed persistent fever, lymphadenopathy and pancytopenia in September of 2000. Hemophagocytes were found in the bone marrow smears. Epstein-Barr virus (EBV) serology showed positive for VCA-IgG, IgM and EB-ER and negative for EBNA. The EBV genome was detected in the peripheral blood. The patient was diagnosed as having EBV-associated hemophagocytic syndrome (EBV-AHS) and received chemotherapy. Although she was treated with lamivudine three months after the initiation of chemotherapy, she developed severe hepatitis. She recovered from the hepatitis through a combination of plasma exchange, immunosuppressive and antiviral therapies. Because of the refractoriness of her EBV-AHS to chemotherapy, she received allogeneic peripheral blood stem cell transplantation (PBSCT) from her HLA-identical brother. Hepatitis B did not recur after the PBSCT under administration of lamivudine. The EBV genome in the peripheral blood disappeared soon after the PBSCT but it was revealed again after the initiation of prednisolone for the treatment of acute GVHD. A donor lymphocyte infusion (DLI) was given on day 169 and the EBV genome copy number in the peripheral blood gradually decreased and disappeared. Although the origin of the EBV-infected cells could not be determined as being from the host or donor, DLI was a useful treatment for the recurrence of EBV infection after allogeneic stem cell transplantation for EBV-AHS.