BACKGROUND: The aim of the present study was to assess the early clinical outcome in elderly patients (aged���75 years) with acute myocardial infarction compared to younger patients (< 75 years). METHODS: The study population included 1315 consecutive patients (mean age 63 짹13 years) registered in KAMIR from January 2006 to April 2007. Elderly patients accounted for 18.1% (238 of 1315) of all patients. ST elevation MI (STEMI) accounted 60.4% (794 of 1315) and there was no statistical difference between elderly and younger patients. The treatment strategy (primary PCI or thrombolysis in STEMI, and early invasive or conservative therapy in NSTEMI) was selected by treating physician. Coronary angiography was done in 95.2% of all patients. The primary endpoint was the in-hospital rate of major adverse cardiac events (including death, stroke, reinfarction, target vessel revascularization and new onset of heart failure). RESULTS: Elderly patients were more frequently female (54.6 vs. 24.2%, p<0.001) and their smoking rate was lower (19.3 vs. 47.4%, p<0.001). They had more atypical symptom at presentation (23.9 vs. 15.2%, p=0.04) and a lower ejection fraction (49.6 vs. 53.7%, p=0.03). Of patients with STEMI, despite a similar rate of TIMI 0-1 flow at presentation (49.6 vs. 52.8%, p=NS), and of glycoprotein IIb/IIIa inhibitor infusion (13.1 vs. 15.7%, p=0.02), the final rate of TIMI 3 flow was significantly lower (67.2 vs. 80.5%, p=0.01) and the rate of stent insertion was lower (74.5 vs. 84.9%, p=0.01) in the elderly population. More early conservative therapy were performed in elderly patients with NSTEMI (66.3 vs. 52.4%, p=0.01) but there was no difference in in-hospital mortality. Although the in-hospital ischemic event rates for all ages were not significantly different, the in-hospital mortality was higher in the elderly as compared with younger patients (10.5 vs. 3.0%, p < 0.001). The higher in-hospital mortality in elderly patients was consistent with higher in-hospital mortality in STEMI (15.3 vs. 3.7%, p<0.001). CONCLUSION: Although the treatment strategies of STEMI were not different in all age groups, PCI results were worse and in-hospital mortality was higher in elderly patients.