ABSTRACT Objective: To determine the prevalence of spirometric abnormalities in patients screened for coronary artery disease (CAD) and the risk factors for lung function impairment. Methods: Patients referred for cardiac CT underwent spirometry and were subsequently divided into two groups, namely normal lung function and abnormal lung function. The prevalence of spirometric abnormalities was calculated for the following subgroups of patients: smokers, patients with metabolic syndrome, elderly patients, and patients with obstructive coronary lesions. All groups and subgroups were compared in terms of the coronary artery calcium score and the Duke CAD severity index. Results: A total of 205 patients completed the study. Of those, 147 (72%) had normal lung function and 58 (28%) had abnormal lung function. The median coronary artery calcium score was 1 for the patients with normal lung function and 36 for those with abnormal lung function (p = 0.01). The mean Duke CAD severity index was 15 for the former and 27 for the latter (p < 0.01). Being a smoker was associated with the highest OR for abnormal lung function, followed by being over 65 years of age and having obstructive coronary lesions. Conclusions: The prevalence of spirometric abnormalities appears to be high in patients undergoing cardiac CT for CAD screening. Smokers, elderly individuals, and patients with CAD are at an increased risk of lung function abnormalities and therefore should undergo spirometry. (ClinicalTrials.gov identifier: NCT01734629 [http://www.clinicaltrials.gov/])