The purpose of this study was to assess the characteristics and predictors of subclinical coronary atherosclerosis in young adults. The study also evaluated predictors of cardiac events. We retrospectively enrolled 914 self-referred asymptomatic subjects under the age of 45 (552 men, 362 women) who had undergone both coronary CT angiography (CCTA) and coronary artery calcium scoring. Two radiologists analyzed plaque composition and degree of stenosis. For all subjects, we evaluated clinical risk factors and investigated cardiac events. Subclinical coronary atherosclerosis was found in 86 subjects (9.4 %). Among them, 64 subjects (74.4 %) had a single coronary artery plaque. On analysis of individual segments, the most common type of plaque was non-calcified plaque (NCP) (58 %), which was found in 63 subjects (6.9 %). Significant coronary artery stenosis was found in 9 subjects (0.1 %). Predictors of subclinical coronary atherosclerosis were age, male gender, hypertension, and diabetes mellitus. Male gender, diabetes mellitus, and amount of smoking were independent predictors of NCP. High low density lipoprotein cholesterol and calcium scores were also significant predictors of stenosis. Myocardial infarction developed in 1 subject, unstable angina in 2, stable angina in 1, and death in 1 (2.45 cardiac events per 1,000 person-years of follow-up). Multivariate analysis revealed hazard ratios of 2.2 for subclinical coronary atherosclerosis, 49.17 for NCP, and 105.58 for significant stenosis. The prevalence of subclinical coronary atherosclerosis in asymptomatic young adults is not negligible. CCTA has the potential to enhance risk stratification and prediction for coronary artery disease in asymptomatic young adults.