Background: Recent studies have demonstrated the quantitative ability of contrast-enhanced multidetector computed tomography (MDCT) to evaluate not only the vessel lumen but also coronary plaque. The aim of this study was to assess the association between coronary wall thickness quantified by 64-slice MDCT and cardiovascular risk factors. Methods and Results: A total of 149 subjects with suspected coronary artery disease were scanned by contrast-enhanced 64-slice MDCT. The maximum coronary wall thickness of each proximal segment was measured and associations with baseline coronary risk factors were analyzed. The mean maximum wall thickness of all 149 patients was 0.7 ±0.3 mm and there was a significant positive correlation with age (P<0.001) and hemoglobin (Hb) A_1c (P=0.001). Patients with hypertension (0.8 ±0.3 vs 0.7 ±0.3 mm, P=0.024) and diabetes (0.9 ±0.4 vs 0.7 ±0.3 mm, P=0.002) had thicker walls than those without. Multivariate linear regression analysis demonstrated that both risk factors were independently correlated with mean maximum wall thickness. Conclusions: Coronary wall thickness measured by 64-slice MDCT is associated with age and HbA_1c, so may add useful information to cardiovascular risk stratification. (Circ J 2009; 73: 681 - 685)