Although several studies describe the prevalence of coronary artery disease in patients with abdominal aortic aneurysms (AAA), the opposite relationship is virtually unexplored. It is the purpose of this study to determine the prevalence of AAA in patients with severe coronary artery disease undergoing bypass grafting (CABG). Patients scheduled for elective CABG underwent aortic ultrasound (US) preoperatively. A control group of patients without cardiovascular disease also underwent US. An AAA was defined as a maximal diameter > or =3.0 cm. US was performed on 192 CABG patients and 140 controls. The overall prevalence (previously repaired AAA and new cases) of AAA in CABG patients was 18.2%. The prevalence of new cases of AAA was 13.0% compared to 1.4% in controls (p = 0.0001). Ten patients had an AAA greater than 5.0 cm in size (5.2%). Logistic regression identified age > or =65 years and smoking as significant risk factors for AAA in the CABG population. The higher prevalence of AAA in CABG patients was confirmed by a case-control analysis of 73 age-matched patients. This study provides the first convincing evidence that the prevalence of AAA is higher in patients undergoing CABG than in the control population in Vermont. Consideration should be given to screening patients for AAA who are undergoing CABG, particularly older, smoking males.