BACKGROUND: With the widespread use of cardiac multidetector row computed tomography (MDCT), the issue of incidental findings is receiving increasing attention. Our objectives were to evaluate the prevalence of incidental findings discovered during cardiac MDCT scanning and to identify clinical variables associated with incidental findings. METHODS: This cross-sectional analysis involved a population-based sample recruited from an integrated health care delivery system in Northern California as part of the Atherosclerotic Disease, Vascular Function and Genetic Epidemiology (ADVANCE) Study. Healthy men and women aged 60 to 69 years without diagnosed cardiovascular disease underwent cardiac MDCT for the detection and quantification of coronary artery calcification. The images were prospectively evaluated for incidental findings. RESULTS: A total of 459 participants underwent MDCT scanning, and the overall prevalence of any incidental finding was 41%. Of the 459 participants, 105 (23%) had at least 1 incidental finding that was recommended for clinical or radiological follow-up examination, the most common of which was single or multiple pulmonary nodules (18%). Participants with and without incidental findings had comparable baseline demographics and selected clinical variables, although there were significantly fewer men and a significantly lower prevalence of the metabolic syndrome in those with incidental findings. CONCLUSIONS: Incidental findings, especially pulmonary nodules, are common in cardiac MDCT performed to assess coronary artery calcification in older healthy adults. The net risks and benefits of looking for noncardiac abnormalities during cardiac MDCT should be rigorously evaluated.