BACKGROUND: Evidence regarding the primary prevention of coronary artery disease events by low-density lipoprotein cholesterol (LDL-C) lowering therapy in older individuals, aged ≥75 years, is insufficient. This trial tested whether LDL-C-lowering therapy with ezetimibe is useful for the primary prevention of cardiovascular events in older patients. METHODS: This multicenter, prospective, randomized, open-label, blinded end-point evaluation conducted at 363 medical institutions in Japan examined the preventive efficacy of ezetimibe for patients aged ≥75 years, with elevated LDL-C without history of coronary artery disease. Patients, who all received dietary counseling, were randomly assigned (1:1) to receive ezetimibe (10 mg once daily) versus usual care with randomization stratified by site, age, sex, and baseline LDL-C. The primary outcome was a composite of sudden cardiac death, myocardial infarction, coronary revascularization, or stroke. RESULTS: Overall, 3796 patients were enrolled between May 2009 and December 2014, and 1898 each were randomly assigned to ezetimibe versus control. Median follow-up was 4.1 years. After exclusion of 182 ezetimibe patients and 203 control patients because of lack of appropriate informed consent and other protocol violations, 1716 (90.4%) and 1695 (89.3%) patients were included in the primary analysis, respectively. Ezetimibe reduced the incidence of the primary outcome (hazard ratio [HR], 0.66; 95% CI, 0.50-0.86; P=0.002). Regarding the secondary outcomes, the incidences of composite cardiac events (HR, 0.60; 95% CI, 0.37-0.98; P=0.039) and coronary revascularization (HR, 0.38; 95% CI, 0.18-0.79; P=0.007) were lower in the ezetimibe group than in the control group; however, there was no difference in the incidence of stroke, all-cause mortality, or adverse events between trial groups. CONCLUSIONS: LDL-C-lowering therapy with ezetimibe prevented cardiovascular events, suggesting the importance of LDL-C lowering for primary prevention in individuals aged ≥75 years with elevated LDL-C. Given the open-label nature of the trial, its premature termination and issues with follow-up, the magnitude of benefit observed should be interpreted with caution. Clinical Registration: URL: https://www.umin.ac.jp. Unique identifier: UMIN000001988.