Background: This analysis from the Korea Acute Myocardial Infarction Registry (KAMIR) assessed the beneficial effect of angiotensin II receptor blocker (ARB), angiotensin converting enzyme (ACE) inhibitor, and combination of both drugs for the improvement of long term clinical outcomes in acute myocardial infarction (AMI) patients with renal dysfunction. Method: 6125 AMI patients (65.2 짹 12.0 years, 4461 males) who underwent successful percutaneous coronary intervention and survived in hospital period and followed-up during one year after discharge were divided into four groups according to creatinine clearance (CrCl): Group I [normal renal function, CrCl���90 ml/min (n=1255)]; Group II [mild renal dysfunction, 60���CrCl<90 ml/min (n=2603)], Group III [moderate renal dysfunction, 30 ��� CrCl < 60 ml/min (n=1952)], Group IV [severe renal dysfunction, 30 < CrCl ml/min (n=315)]. Each group were divided into 4 subgroups according to ACE inhibitor or ARB treatment [ACE inhibitor alone group, ARB alone group, combination group, and control group (no ACE inhibitor or ARB)]. We retrospectively evaluated the effects of ARB, ACE inhibitor, and combination of the two drugs on major adverse cardiac events (MACE), including cardiac death, reinfarction, coronary artery bypass grafting, heart failure requiring rehospitalization, and target lesion revascularization during one-year clinical follow up. Result: At one-year clinical follow up, there was no significant difference in the rate of MACE between ARB alone group and ACE inhibitor alone group in group I, II, III. And as compared with the control group, both the ARB alone group and ACE inhibitor alone group had lower rates of MACE in group I, II, III. Importantly, the combination group had a higher rate of MACE compared with the ARB alone group and ACE inhibitor alone group in group I, II, III. But there was no significant difference in the rate of MACE between ARB alone group and ACE inhibitor alone group, combination group, control group in group IV. Conclusion: The beneficial effects of ARB were equivalent to those of ACE inhibitor and the combination of the two drugs was associated with more adverse events without an increase in benefit in AMI patients with normal renal function and mild to moderate renal dysfunction.