A 23-year old woman was admitted to our hospital because of fever, leukocytopenia, thrombocytopenia and cervical lymphadenopathy. From pathological findings of the cervical lymphnode she was diagnosed as subacute necrotizing lymphadenitis (SNL). Bone marrow aspiration was hypocellular with proliferation of mature histiocytes with hemophagocytosis. Lactate dehydrogenase was elevated to 1863 IU/l and mild liver dysfunction was observed. Hepatosplenomegaly, lymphnode swelling in abdominal cavity, pleural effusion and pericardial effusion were detected. After glucocorticoid therapy all such disorders were normalized. In this course, Epstein-Barr (EB) virus genome was detected by a polymerase chain reaction method from peripheral mononuclear cells. After normalization, EB virus genome became not to be detected. From present case we concluded that EB virus was expanded in clinical course and was associated with pathogenesis of SNL.