BACKGROUND: There are controversies regarding the usefulness of coronary artery calcium score (CACS) for predicting coronary artery stenosis. The aim of this study was to determine the prognostic value of CACS for determining the presence and severity of coronary artery disease (CAD) in patients with sign and symptoms of the disease. MATERIAL AND METHODS: In this cross-sectional study, 748 consecutive patients with suspected CAD, referred for coronary computed tomography angiography (CCTA), were enrolled. The mean CACS was compared between patients with different severities of coronary artery stenosis. The association between CACS and different CAD risk factors was determined as well. Different cutoff points of CACS for discriminating between different levels of coronary artery stenosis was determined using receiver operating characteristic (ROC) curves. RESULTS: The mean CACS was significantly different between different levels of coronary artery stenosis (P<0.001) and there was a significant positive association between the severity of CAD and CACS (P<0.001,r=0.781). ROC curve analysis indicated that the optimal cutoff point for discriminating between CAD (presence of stenosis) and the non-stenosis condition was 5.35 with 88.6% sensitivity and 86.2% specificity. Area under the curve for different levels of coronary artery stenosis did not have sufficient sensitivity and specificity for discriminating between different levels of CAD severity (<70%). CONCLUSIONS: The study demonstrated that there is a significant association between CACS and the presence as well as the severity of CAD. CACS could have an appropriate prognostic value for the determination of coronary artery stenosis but not for discriminating between different severities of stenoses.