PURPOSE: Abdominal aortoiliac artery aneurysm (AIAA) is a common disease in the elderly. The prevalence of AIAA was well known in western countries. However, in Korea, there are a few studies regarding the prevalence. This study was carried out to determine the prevalence of AIAA by reviewing the radiological reports of abdominal computed tomography (CT). METHODS: We searched the words like "aneu" or "rysm" in radiological reports of 22,520 abdominal CT (11,974 patients) between January 1, 2005 and March 31, 2010 in patients over 50 years old. We found 121 patients who had AIAA of more than 3 cm or more than 1.8 cm isolated iliac artery aneurysm. We analyzed the characteristics of these patients with aneurysm. RESULTS: The prevalence of aneurysms was 1.01% (121 patients). The aneurysms in men were more prevalent than women (1.39% vs. 0.51%). In the octogenarian, the aneurysms were found to be most frequent (2.75%). Among the 121 aneurysms, aortic, aortoiliac, and isolated iliac artery aneurysms were 66 (54.6%), 28 (23.1%), and 27 (22.3%). In terms of aneurysmal size, greater than 6 cm, 5 to 6 cm, and less than 5 cm were 19 (20%), 13 (14%), and 62 (66%), respectively. The rupture rate was 18% (6 patients) in more than 5 cm abdominal aortic aneurysm. CONCLUSION: The prevalence of AIAA is lower than Western countries. This is not a national-wide survey, but results are similar to the other Korean reports. Reviewing radiologic reports of abdominal CT is another way to study the prevalence of aneurysms.