PURPOSE: The purpose of this study was to determine the relation of aortic wall thickness (AWT), aortic calcification (AC), and aortic distensibility (AD) to severity of coronary artery disease (CAD). MATERIALS & METHODS: From July 2008 until June 2009, among the consecutive patients who underwent cardiac CT angiography (CCTA) to rule out CAD, 116 patients with CCTA finding of significant luminal stenosis or discordant image finding with symptom underwent invasive coronary angiography. The severity of CAD was assessed by 3 methods; Gensini score, segment stenosis score (SSS) and segment involvement score (SIS). We measured AWT at the thickest portion of the descending thoracic aorta. We quantified AC, which ranged from upper edge of aortic arch to the cardiac apex using coronary calcium score software. AD was calculated by difference of maximum and minimum area of aorta and pulse pressure which measured during CT scan. RESULTS: Twenty eight patients were subclinical CAD, 40 patients were 1 vessel-disease, 23 patients were 2 vessel-disease, and 25 patients were 3 vessel-disease. AWT and AD of ascending aorta were significantly different between 0~3 vessel disease groups on one-way ANOVA test. AWT and AC were positively and AD of ascending and descending thoracic aorta was negatively correlated with all 3 methods assessing severity of CAD on Pearson���s correlation test.. Among aortic parameters, AWT was mostly correlated with severity of CAD (Gensini score: r=0.318, p=0.001; SSS: r=0.338, p<0.001; SIS: r=0.228, p=0.002). CONCLUSION: Our study showed a significant relationship between the aortic wall thickness, aortic calcification and aortic distensibility with severity of coronary artery disease. Especially, amongst the three factors, the aortic wall thickness was the most strongly associated factor relating to the severity of CAD.