We previously reported 24 cases of marrow fibrin-ring granuloma (FRG) encountered in 1 institution and concluded that, contrary to previous studies showing marrow FRG as a diagnostic marker for Q fever, Epstein-Barr virus (EBV) was the most common proven cause of such FRG. The present study characterized patients with EBV-associated marrow FRG. We retrospectively reviewed 17 cases of EBV-associated FRG (43% of 40 cases with marrow FRG) diagnosed by bone marrow biopsy. Patients with EBV-associated hemophagocytic lymphohistiocytosis (5/17 patients) and chronic active EBV infection (4/17) constituted 53% of patients with EBV-associated FRG. Three patients had lymphoma without marrow involvement. All patients except 1 presented first with fever; splenomegaly was the next most common clinical finding (12/17). Cytopenia was observed in the 17 cases: anemia in 16, thrombocytopenia in 9, and leukopenia in 8. Patients with EBV-associated FRG showed lower survival outcomes than did patients without EBV (median, 3.0 vs 11.8 months; P = .009). Patients with bone marrow FRG accompanied by fever require careful evaluation to discern whether active EBV infection is involved because the prognosis is poor.