Objective To investigate the in-hospital mortality and risk factors among the elderly acute myocardial infarction (AMI) patients at different ages. Methods The clinical data of 883 elderly AMI patients hospitalized in our department from December 2006 to January 2012 were collected and retrospectively analyzed. They were assigned into 2 groups based on their age: old group (60 to 74 years old, n＝473), and very old group (75 to 89 years old, n＝410). Their general condition, medical history and family history, admission examination, clinical diagnosis, complications, treatment and in-hospital mortality were compared and analyzed. Results The old group had significantly lower in-hospital mortality than very old group (5.9% vs 14.6%, P＝0.000). There were significantly more patients undergoing percutaneous coronary intervention (PCI) in old group than in very old group(92.6% vs 69.8%, P＝0.000). The in-hospital mortality was positively correlated with the increased levels of blood urea nitrogen, blood glucose, white blood cells and brain natriuretic peptide (BNP). Complications with arrhythmia (sinus arrest, ventricular and atrial fibrillation), cardiogenic shock and Killip3-4 group, placement of intra-aortic balloon counterpulsation (IABP), and no surgical treatment were also positively correlated with in-hospital mortality. And it was negatively correlated with receiving drugs [angiotensin converting enzyme inhibitors (ACEI)/angiotensinⅡreceptor blockers (ARB), β-blockers and statins]. High level of blood urea nitrogen, complications with sinus arrest and cardiogenic shock, and no surgical treatment were independent risk factors for in-hospital mortality in both groups. Conclusion Application of PCI improves prognosis of the elderly patients with AMI. More attention should be paid to blood urea nitrogen and complications such as sinus arrest and cardiogenic shock.