We report here, a patient of systemic lupus erythematosus (SLE) with severe fibrinoid necrosis in the afferent arteriole of the glomerulus, in whom antiphospholipid antibody might have contributed to the pathogenesis. A 24-year-old female who was suffering from severe anemia with fragmented red blood cells, acute renal failure and thrombocytopenia, was admitted to our hospital. Further examinations revealed findings compatible with active lupus nephritis. Moreover, she was found to be positive for antiphospholipid antibody, and anticardiolipin antibody, as well as for lupus anticoagulant and syphilis test. Intensive treatment by methylprednisolone pulse therapy, hemodialysis, and double filtration plasmapheresis were performed. However, 13 days after admission she died suddenly because of intracranial hemorrhage. Pathological investigation of renal tissue revealed severe fibrinoid necrosis of the arterioles mainly in the glomerular afferent arteriole associated with diffuse proliferative lupus nephritis. In this case, hemolytic uremic syndrome (HUS) was associated with SLE. Antiphospholipid antibody was considered to be not only an accelerator in the arterial lesions of HUS, but also an initiator of HUS itself.