Background: Abdominal aortic aneurysm (AAA) is a fatal disease if the diagnosis is delayed. We previously proposed the routine screening protocol for AAA during clinical transthoracic echocardiography (TTE). Coronary artery disease (CAD) shares several risk factors with AAA and possibly associated with higher prevalence of AAA than normal population. In patients with significant CAD who are scheduled for cardiac catheterization, TTE is clinically performed before cardiac catheterization. We evaluated the efficacy of routine screening protocol for AAA during clinical TTE in patients who has significant CAD. Methods: TTE was performed before cardiac catheterization for routine clinical practice. Screening protocol for AAA was added at the end of TTE protocol. From August 2009 to May 2010, patients who were diagnosed as significant CAD were included. Significant CAD was defined as a narrowing more than 50% in diameter of epicardial segment of the coronary artery by quantitative coronary angiography. The aorta was considered AAA when the maximal diameter of infra-renal abdominal artery was of 30 mm or more. Results: A total of 1590 patients were screened, and reliable measurement of abdominal aorta size was available in 812 patients. AAA was diagnosed in 15 patients (1.48%), 12 of whom were male (80% of AAA patients). The mean age of AAA patients was 68.1years old, and 80% of AAA patients were over 68 years old. Patients with AAA were older than those without AAA (68.1 vs 64.1 years). Peripheral vascular disease was more prevalent in patients with AAA than who without AAA (p<0.001). The prevalence of AAA is higher in patients who have significant CAD than previously reported in normal Korean populations (0.5%). Peripheral vascular disease was significantly associated with CAD patients with AAA than CAD patients without AAA Conclusions: The prevalence of abdominal aortic aneurysm is higher in patients with CAD than normal populations and associated with peripheral vascular disease. In-hospital echocardiographic screening of AAA is efficient among patients with CAD patients and possibly helpful to decide the vascular approach during cardiac catheterization.