Surgical management of patients with simultaneous coexisting malignancy of the digestive organs and an abdominal aortic aneurysm (AAA) remains controversial. In the five patients who underwent the aneurysmectomy first, no complications developed after an aneurysmectomy and a resection of malignancy could be performed within 4 weeks, whereas postoperative complications after the resection of malignancy developed in two of them. Two patients underwent a one-stage operation, in which one was unable to tolerate the two procedures, and no postoperative complications were seen; however, one patient with cardiac dysfunction who first underwent an aneurysmectomy died 3 months after operation due to cardiac and renal failure. These results indicate that the aneurysmectomy first is preferred, when such patients do not have absolute indications of malignancy or AAA; however, a one-stage operation should be chosen when the patients show a disturbance of key organs.