Abstract Background & objectives: Acute myocardial infarction is the single most common cause of death in large parts of the world. Although the mortality rate after admission for myocardial infarction has declined significantly over the last two decades but it still remains high. Therefore, the aim of this study was to determine hospital mortality and its related factor in patients with acute myocardial infarction hospitalized in Dr. Heshmat hospital. Material & Methods: In this cross-sectional study, we assessed medical records of 227 patients with acute Myocardial Infarction that hospitalized in CCU. Demographic and clinical factors were collected from the medical records. Data analysis was performed using SPSSv.16 software at P>0.05. Results: In-hospital mortality rate of acute myocardial infarction patients was 8.4%. In univariate analysis, condition of patients with acute myocardial infarction after hospitalization was related with number of hospitalization days (P<0.002), left ventricular ejection fraction (P<0.002) and previous history of acute myocardial infarction (P<0.014). In regression analysis, only left ventricular ejection fraction was related with Hospital mortality rate (P<0.019, OR=0.885). Conclusion: Despite applying of preventive programs and therapeutic improvements, hospital mortality rate also is high (8.4%).In present study, hospital mortality was related with number of hospitalization days, left ventricular ejection fraction and previous history of acute myocardial infarction.