The incidence of isolated iliac artery aneurysm is 1-2% of that of abdominal aortic aneurysms. The natural history is of gradual enlargement, with rupture the most common clinical presentation. The signs and symptoms of such an aneurysm are influenced by its concealed location within the bony pelvis. Awareness of these special characteristics improves the chances of early diagnosis and proper surgical treatment before possible rupture. We report 2 cases which demonstrate the spectrum of the clinical presentation.