A case of angiotropic B-cell lymphoma associated with hemophagocytic syndrome (HPS) has been reported. In addition to fever, pancytopenia, hepatosplenomegaly, and lack of lymphadenopathy, unique clinical features, such as syndrome of inappropriate secretion of antidiuretic hormone (SIADH) and pulmonary infarction, were manifested. Both soluble interleukin-2 receptor (sIL-2R) and IL-6 were elevated in the patient's sera in addition to an increase of serum lactate dehydrogenase and ferritin. In contrast, tumor necrosis factor-alpha and interferon-gamma were within normal ranges. Serum antibodies against Epstein-Barr virus and cytomegalovirus showed a past infection pattern. An autopsy examination revealed systemic intravascular proliferation of lymphoma cells with a B-cell phenotype, confirming the diagnosis of angiotropic B-cell lymphoma. Moreover, SIADH was suggested to result from the infiltration of tumor cells into the pituitary gland. Triple association of angiotropic B-cell lymphoma, HPS and SIADH is quite rare. Therefore, the present case seems to be helpful for clarifying the mechanism for HPS of non-Hodgkin's lymphoma with B-cell origin.