BACKGROUND The prevalence of coronary artery disease (CAD) increases in patients with moderate to severe renal insufficiency. The impact of renal insufficiency on the development of CAD may increase as renal function continues to deteriorate; however, there is no available data in mild renal insufficiency. The purpose of this study was to explore the association between mild renal insufficiency and coronary atherosclerosis, using coronary CT angiography (CCTA). METHODS We consecutively enrolled 4941 asymptomatic subjects (mean age 49 짹 10 years, 61% male), who underwent CCTA (64-slice MDCT) as part of a general health evaluation. We categorized subjects based on their estimate of renal function (estimated glomerular filtration rate (eGFR), using MDRD equation: ���60 vs. 45 to 59 ml/min/1.73 m2). Patients with eGFR less than 45 ml/min/1.73 m2 were excluded. Coronary artery calcium score (CACS), presence of coronary plaque, and significant stenosis (���50% lumen diameter) were compared between 2 groups. Regression analysis was performed to assess the correlation between CAD and mild renal insufficiency. RESULTS Three hundreds thirty-six subjects (7%) had mild renal insufficiency (eGFR: 45 to 59) and 4591 (93%) had normal renal function (eGFR: ���60 ml/min/1.73 m2). Subjects with mild renal insufficiency showed higher incidence of presence of coronary plaque (123 (37%) vs. 1010 (22%), p<0.001), significant stenosis (31 (9%) vs. 142 (3%), p<0.001), and moderate to severe CACS (45 (13.4%) vs 204 (4.4%), p<0.001). However, after adjusting conventional risk factors, mild renal insufficiency was no longer an independent risk factor for the presence of plaque and significant stenosis. Age, male sex,and albuminuria were independent risk factor for both the presence of plaque and significant stenosis. CONCLUSIONS The higher incidence of CAD and significant stenosis in subjects with mild renal insufficiency was observed, however, which are primarily attributed to the effect of other conventional risk factors. Mild renal insufficiency may not act as an independent risk factor for coronary atherosclerosis