Our aim was to analyze its diagnostic and prognostic value in patients with high coronary calcium score (CCS). A total of 113 patients with CCS > 400 were included. Significant coronary artery disease (CAD) was defined as stenosis ≥ 50%. Invasive coronary angiography and major cardiovascular events were recorded. The CCS and heart rate during the acquisition were significantly lower in the diagnostic coronary computed tomography angiography (CCTA) group. The cut-off value of CCS to establish the diagnostic utility of CCTA was 878. The rate of cardiovascular events was 9.3%. The positive predictive value of CCTA to detect significant CAD was 73.5% and the negative predictive value for predicting cardiovascular events was 96%. In patients with high CCS, CCTA is useful to evaluate CAD, especially when the CCS is lower or equal to 878; moreover, the prognostic value of CCTA is better in patients where significant CAD has been ruled out.