We report the case of a 61-year-old female who suffered from systemic lupus erythematosus (SLE) and died of a ruptured abdominal aortic aneurysm (AA). She was diagnosed to have SLE at 39 years of age, and was administrated steroids and prostaglandin E(2). From 52 years of age, AA, peripheral arterial occlusion, and multiple organ infarctions appeared repeatedly. At 59 years of age, she was found to be affected by antiphospholipid antibody syndrome (APS). In the following year, expansion of an abdominal AA was identified, but she was given only conservative treatment. In the next year, sudden epigastralgia and dyspnea occurred, and she died. An autopsy revealed multiple AAs up to 11 cm in diameter, one of which showed ruptures, forming a retroperitoneal hematoma. Marked atherosclerosis of the aorta was noted, and she also had aortic dissection accompanied by cystic medial necrosis (CMN). An old myocardial infarction and brain infarction were also confirmed. Although SLE with APS is common, a complication of the disease by CMN, multiple AAs, or ruptured AA has been described in several cases to date. Regarding the etiology of this complicated presentation, we presume synergistic involvement of various factors, such as atherosclerosis and CMN associated with SLE, thrombosis due to APS, and prolonged steroid therapy.