Background: and Purpose The American College of Cardiology and the American Heart Association (ACC-AHA) have released new guidelines and expanded indications for statin treatment. We aimed to reveal the clinical efficacy of each indication in the guidelines using a large-scale national cohort. Methods: We used National Health Screening Cohort data to determine the proportions of participants for whom statin therapy would be recommended using the different guidelines.We assessed the cumulative incidence rates of major adverse cardiovascular events (MACE) using the Cox proportional-hazards model. Results: Under the 2013 ACC-AHA guidelines, 111,600 participants were additionally eligible to receive statins, compared with 50,023 participants according to the Third Adult Treatment Panel (ATP-III). Most of the additional statin-eligible participants in the ACC-AHA guidelines were indicated by their 10-year cardiovascular disease risk. The increase in statineligible participants in the ACC-AHA guidelines mainly involved elderly patients aged 60–75 years. Among participants not requiring statin, participants who were eligible for a statin under the ACC-AHA guidelines had a significantly higher hazard ratio of MACE when compared with those eligible under the ATP-III guidelines. Among the not-recommended groups, patients with diabetes and low-density lipoprotein <70 mg/dL constituted the group with the highest risk of MACE. Conclusions The 2013 ACC-AHA guidelines increase the number of statin-eligible participants, especially among the elderly. These guidelines provide a stronger recommendation for statins to high-risk groups, but it remains necessary to consider the characteristics of the population in the risk equation. In addition, the aggressive use of statin in diabetes patients and further studies of older subjects are needed.