It remains inconclusive whether the additional low-density lipoprotein cholesterol (LDL-C) lowering effects of ezetimibe added to statin on coronary atherosclerosis and clinical outcomes are similar to those of statin monotherapy in the setting of comparable LDL-C reduction. We aimed to determine whether there were distinguishable differences in their effects on coronary atherosclerosis with intermediate stenosis between the combination of moderate-intensity statin plus ezetimibe and high-intensity statin monotherapy. Forty-one patients with stable angina undergoing percutaneous coronary intervention were randomized to receive either atorvastatin 10 mg plus ezetimibe 10 mg (ATO10/EZE10) or atorvastatin 40 mg alone (ATO40). The intermediate lesions were evaluated using a near-infrared spectroscopy-intravascular ultrasonography at baseline and after 12 months in 37 patients. The primary endpoint was percent atheroma volume (PAV). Mean LDL-C levels were significantly reduced by 40% and 38% from baseline in the ATO10/EZE10 group (n = 18, from 107 mg/dL to 61 mg/dL) and ATO40 group (n = 19, from 101 mg/dL to 58 mg/dL), respectively, without between-group difference. The absolute change of PAV was -2.9% in the ATO10/EZE10 group and -3.2% in the ATO40 group. The mean difference (95% confidence interval) for the absolute change in PAV between the 2 groups was 0.5% (-2.4% to 2.8%), which did not exceed the pre-defined non-inferiority margin of 5%. There was no significant reduction in lipid core burden index in both groups. In conclusion, the combination of atorvastatin 10 mg and ezetimibe 10 mg showed comparable LDL-C lowering and regression of coronary atherosclerosis in the intermediate lesions, compared with atorvastatin 40 mg alone.