BACKGROUND: Fibrin-ring granuloma (FRG), which can be found in bone marrow or the liver, is a subtype of epithelioid granuloma characterized by a central fat vacuole and annular peripheral fibrinoid materials. FRG has been proven to be associated with many etiologies such as several infectious organisms (Coxiella burnett; Epstein-Barr Virus, EBV; cytomegalovirus, CMV; and hepatitis A virus), allopurinol induced hepatitis, Hodgkin's lymphoma, and peripheral T-cell lymphoma. METHODS: We retrospectively reviewed 24 patients diagnosed with FRG by bone marrow biopsy at a single institute between 1995 and 2004. We reviewed clinical symptoms and laboratory findings of the patients, classified them by etiology, and compared prognosis of each group. RESULTS: The most common cause of FRG was acute or chronic EBV infection. Chronic or acute EBV infection was associated with 41.4% of patients (10/24). Of the remaining patients, 33.3% (8/24) were leukemia or lymphoma patients after chemotherapy, 4.2% (1/24) was a patient with hepatic failure, and 20.8% (5/24) were diagnosed as fever of unknown origin. The most common symptom and clinical finding were fever and cytopenia. EBV-associated group comprised chronic active EBV infection, EBV-associated hemophagocytic histiocytosis, acute EBV infection, EBV-associated lymphoproliferative disease, and Langerhans' cell histiocytosis. The EBV-associated group showed a lower survival probability compared with the non-EBV group (P<0.05). CONCLUSIONS: Patients with bone marrow fibrin ring granuloma accompanied by fever require an active workup to find out the cause of infectious agents including EBV infection particularly due to their poor prognosis.