Background. Recent reports have shown that miR-145 concentration correlates with infarct size. In this paper, we attempt to predict heart failure and cardiovascular death after acute myocardial infarction using circulating miR-145 concentration. Methods. We assessed 246 patients with first ST-segment-elevation myocardial infarction who underwent successful percutaneous coronary intervention. We measured circulating miR-145, N-terminal fragment of the precursor B-type natriuretic peptide, myocardial-band creatine kinase, and cardiac troponin-I concentrations on day 5 after primary percutaneous coronary intervention and assessed their correlations with long-term clinical outcome. Results. During the one-year follow-up period, 72 patients experienced primary composite cardiac events (cardiac death or hospitalization for worsening heart failure). Multivariable Cox proportional hazards analysis indicated that circulating miR-145 (hazard ratio 7.174, 95% confidence interval 4.208-12.229); p < 0.0001) was a significant independent predictor of cardiac events after adjustment for multiple confounders. Conclusion. Circulating miR-145 may be a novel biomarker for predicting long-term outcome after acute myocardial infarction.