Background: Arterial stiffness is a physiologic quantitative value used to measure arterial compliance. It is predictive of coronary atherosclerosis in patients with intermediate to high cardiovascular risk. However, a correlation between arterial stiffness and subclinical coronary atherosclerosis has yet to be established. Therefore, the purpose of this study was to evaluate arterial stiffness using an arterial stiffness index (ASI) and investigate its association with coronary artery plaque in patients with subclinical coronary atherosclerosis. Methods: Our study enrolled 156 consecutive subjects who underwent health screening using a 64-slice cardiac computed tomography angiography (CCTA). Their arterial stiffness index was assessed noninvasively by CardioVision® MS-2000. The atheroma on the coronary vessel walls was analyzed. Results: Of the 156 patients, 53 displayed at least one > 50% stenotic lesion over the coronary arteries in CCTA images. The patients with at least one > 50% coronary stenotic plaque were older and had higher systolic blood pressure and ASI values than patients without > 50% coronary stenotic plaque. After dividing the study population into 2 groups by those patients over and under 50 years of age, the ASI positively correlated with the presentation of at least one > 50% coronary stenotic plaque in patients aged ≥ 50 years (odds ratio = 1.02, 95% confidence interval: 1.00-1.04, p = 0.03). Conclusions: The ASI could play a role in risk stratification systems for coronary artery disease in patients with subclinical coronary atherosclerosis, and is a useful clinical marker for the correlation of early coronary plaque.