A 38 year old woman with systemic lupus erythematosus (SLE) was admitted because of epigastralgia and fever. The diagnosis of SLE was made 22 years ago based on Raynaud's phenomenon, butterfly rash, hair loss, photosensitivity and positive antinuclear antibody. She had episodes of consciousness disturbance, transient visual disturbance of the left eye, and a necrosis of the left big toe. She underwent artificial arthroplasty of bilateral femoral heads 11 years ago, when multiple aseptic necroses of thirteen bones were found, and when anti-cardiolipin (CL) antibody was found to be positive. An echogram of abdomen suggested an obstruction of superior mesenteric artery (SMA) when she was admitted. Selective angiography revealed a complete obstruction of SMA and splenic artery, and incomplete obstruction of celiac artery. Conservative treatment with urokinase infusion and prednisolone 50 mg/day was not effective, and small intestine and right colon were resected on the 23rd hospital day. The pathological examination showed thrombosis of SMA. There was no evidence of arteritis or atherosclerosis. Anti-CL antibody and lupus anticoagulant were positive on admission, but the level of both anti-DNA antibody and complement was normal. Therefore, it was suggested that the thrombosis was related with anti-phospholipid antibody. The characteristic clinical feature were multiple aseptic bone necroses and thromboses of several arteries. We discussed the relationship of thrombosis and the etiology of multiple bone necrosis in this case with anti-phospholipid antibody.