The combination of ezetimibe and a statin provides greater LDL-C reduction by inhibiting both intestinal cholesterol absorption and endogenous production of cholesterol. The present study was designed to examine the influence of ageing, gender, BMI, levels of LDL-C, and HbA1c on the response to ezetimibe add-on therapy. Patients who had been taking a statin for >3 months at the usual dose and whose LDL-C was >120 mg/dL were eligible for this study. Patients were assigned to receive add-on ezetimibe at 10 mg once daily for 12 weeks. Adding ezetimibe to basal statin therapy resulted in a further 15.0% reduction of TC, 20.5% reduction of LDL-C, and 19.7% reduction of non-HDL-C. The change in TC was significantly greater in males than in females. The change in TG was significantly greater in patients with a baseline TG level ≥150 mg/dL. Multivariate regression analysis showed that male sex and LDL-C ≥140 mg/dL were independent predictors of TC reduction after adjustment for age, BMI, and HbA1c. A baseline TG ≥150 mg/dL was also an independent predictor of TG reduction. Addition of ezetimibe to ongoing statin therapy was effective in patients with type 2 diabetes. Male sex and baseline LDL-C levels are independent predictors of marked TC reduction by ezetimibe treatment.