The incidence of abdominal aortic aneurysm and colorectal cancer association is 0.5-1%. This concomitance of two potentially lethal diseases creates a decision making problem regarding priority of treatment. The Authors report a case in which colorectal cancer and abdominal aortic aneurysm were present. This patient first underwent surgery for colorectal cancer, then for aortic aneurysm. Moreover, the Authors review the Literature and discuss their decisional principles about treatment priorities.