We report two elderly male patients with hemophagocytic syndrome (HPS) associated with systemic lupus erythematosus (SLE). They were admitted to the hospital because of general malaise. At admission, they showed fever of unknown origin and hematological abnormalities without typical symptoms for SLE such as arthralgia or malar rash. Chest X-rays, computed tomography and cardiac sonogram demonstrated unilateral pleural and pericardial effusions. Bone marrow aspiration revealed hypocellular marrow with increased macrophages phagocytosing blood cells in the both cases. One patient had positive reactivity for direct Coombs's test and high level of platelet-associated antibody, whose symptoms were ameliorated only by 20 mg per day of prednisolone. The other patient, however, progressive worsened and died regardless of intensive treatment containing methyl-prednisolone pulse therapy. Late-onset lupus (LO-SLE) patients tend to have a more insidious onset of disease, and less frequently show typical symptoms of early-onset SLE such as malar rash. So it seems to be important that clinicians make a fast diagnosis and proper treatment for LO-SLE and associated HPS by careful observation for the latent symptoms and laboratory findings.