Abdominal aortic aneurysms (AAA) are potentially lethal arterial lesions that are best managed by elective surgical repair. However, asymptomatic AAAs may go undetected on routine physical examination or patients with such lesions may not consult a physician. To determine the prevalence of asymptomatic AAAs in a high-risk population, we retrospectively reviewed all abdominal CT scans on veterans >50 years of age that had been ordered for indications other than aneurysmal disease during a recent 10-month period. Of the 111 patients studied, 15 (13.5%) had suprarenal and/or infrarenal AAAs (one patient had both). Patients with AAAs were significantly older (p = 0.0001) and were heavier tobacco users (p=0.003). For patients >60 years of age with peripheral vascular occlusive disease and a history of tobacco use, there was a 29.2% prevalence for AAA compared with 0% in those without any of these risk factors (p = 0.04). There was a very definite trend suggesting that patients with peripheral vascular disease (p=0.06) were more likely to have an AAA. Because of the high prevalence of AAAs found in this population we then conducted a prospective study over a 24-month period during which patients >60 years of age with known peripheral vascular disease and a history of smoking who presented to the vascular laboratory for evaluation of problems not related to AAA were asked to undergo an abdominal CT scan. Fifty-six volunteers agreed to participate in the study. Seven patients had AAAs and one patient had an isolated iliac aneurysm, for a 14.3% overall prevalence of aneurysms. There was no difference in the incidence of risk factors in those patients with aneurysms and those without aneurysms. This represents one of the highest incidences for AAA thus far reported. If immediate repair is not performed, such patients must be followed closely for the development of symptoms or enlargement of their AAA.