Abstract Background The data regarding long-term clinical outcomes according to statin intensity in elderly patients who have undergone percutaneous coronary intervention (PCI) for acute myocardial infarction (MI) is unclear. Purpose We aimed to investigate the long-term clinical benefit of high intensity statin versus moderate to low intensity statin in elderly patients underwent PCI for acute MI. Methods Among 13104 patients with acute MI who have undergone PCI in a nationwide, prospective, and real-world registry, 4294 elderly (defined as ≥70 years) patients prescribed statin at discharge were included. 1136 patients were prescribed with high intensity statin, and 3158 patients were prescribed with moderate to low intensity statin. The major adverse cardiac events (MACE; all-cause death, recurrent MI, any revascularization, stroke, readmission due to heart failure [HF], or definite/probable stent thrombosis [ST]) and the components of MACE were compared in multivariable Cox regression, propensity score (PS) matched, and underwent PS-adjusted analyses. Results During a median follow-up of 998 days, MACE, all-cause death, and cardiac death occurred in 1297 patients (30.2%), 737 patients (17.2%), and 460 patients (10.7%), respectively. The risks of MACE (entire: 26.9% vs. 31.4%, hazard ratio [HR] 0.83, 95% confidence interval [CI] 0.73-0.95, p=0.005; PS-matched: n=2186, 25.3% vs. 30.8%, HR 0.79, 95% CI 0.67-0.94, p=0.008), all-cause death (entire: 14.4% vs. 18.1%, HR 0.78, 95% CI 0.65-0.93, p=0.005; PS-matched: 13.8% vs. 18.9%, HR 0.69, 95% CI 0.57-0.92, p=0.002), cardiac death (entire: 9.5% vs. 11.4%, HR 0.81, 95% CI 0.67-0.97, p=0.042; PS-matched: 8.7% vs. 11.3%, HR 0.77, 95% CI 0.61-0.96, p=0.031), and readmission due to HF (entire: 5.5% vs. 7.5%, HR 0.72, 95% CI 0.55-0.95, p=0.021; PS-matched: 5.7% vs. 8.1%, HR 0.78, 95% CI 0.59-0.96, p=0.017) were significantly decreased in the patients received high intensity statin compared to in those received moderate to low intensity statin. There were no significant differences in the risks of recurrent MI, any revascularization, stroke, and definite/probable ST between the groups. In patients ≥80 years, compared to the moderate to low intensity statin group, high intensity statin group had the reduced rates of MACE, all-cause death, cardiac death, recurrent MI, any revascularization, stroke, readmission due to HF, or definite/probable ST, but insignificantly. Conclusions From the nationwide registry, we noted that in elderly patients after PCI for acute MI the administration of high intensity statin versus moderate to low intensity statin was contributed to the improved long-term clinical outcomes.