Background: Little is known about the risk factors for one year major adverse cardiac events(MACE) among 30 day survivors after acute myocardial infarction (AMI) with low ejection fraction (EF<40%). The aim of the present study was to evaluate the predictors of on year MACE among 30 day post-MI survivors with low ejection fraction from the Korea Acute Myocardial infarction Registry. Methods: 1,644 patients (1171 males, 64.6 짹12.5 year-old) who survived more than 30 days after AMI with low ejection fraction were enrolled from Nov 2005 to Jan 2008. The primary end point was one year MACE including death, myocardial infarction (MI), and target vessel revascularization. Results: During the one year follow up, 218 (13.3%) patients had MACE including 103 (6.26%) deaths, 18 (1.1%) recurrent MI, and 90 (5.5%) target vessel revascularization. In cox proportional hazard analysis, multi-vessel disease [Hazard ratio (HR); 1.437 95% CI=1.151-1.795, p=0.001), cardiogenic shock (HR; 2.124 95% CI=1.128-3.997, p=0.02), and in-hospital complicated acute kidney injury (HR; 6.215 95% CI=1.265-30.534, p=0.024) were independent predictors of one-year MACE after adjustment for clinical, angiographic and procedural data. Plasma N-terminal pro brain natriuretic peptide (NT-pro BNP) level also provided an additional prognostic value predicting one year MACE (HR; 1.622 95% CI=1.173-2.241, p=0.003). The use of angiotensin-converting enzyme inhibitor (ACEI)/angiotensin II receptor blocker (ARB) reduced one year MACE (HR; 0.499 95% CI=0.307-0.812, p=0.005). Conclusions: High NT pro-BNP, multivessel disease, cardiogenic shock, and in-hospital complicated acute kidney injury were associated with increased one year MACE and the use of ACEI/ARB reduced MACE in post-MI survivors with low ejection fraction.