A 55-year-old male on regular hemodialysis was referred to our department for evaluation of intermittent claudication. Abdominal aortography demonstrated occlusion of the abdominal aorta below the superior mesenteric artery. The patient underwent reconstruction of the abdominal aorta by Y-grafting. The occluded abdominal aorta was filled with a gelatin like tumor in which malignant cells were identified histopathologically. Immunohistochemical examination of the malignant cells showed negative results for factor VIII antigen but positive results for actin antigen, which suggested that the cells were of smooth muscle cell origin and the tumor was diagnosed as leiomyosarcoma. The patient's condition gradually deteriorated and he died at eleven months after the initial surgery because of generalized dissemination of the tumor.