Purpose: To compare the demographic data and outcomes of younger versus elderly patients with acute coronary syndromes. Methods: This was a retrospective data bank analysis study with 966 patients (268 in the younger group (less than 55 years) and 698 in the elderly group (more than 55 years)). Data were obtained about clinical characteristics, angiography, and medication used at hospital and coronary definitive treatment. The primary endpoint was all cause of in-hospital death and combined events. Comparison between groups was made by Anova and Q-square. Multivariative analysis was determined by logistic regression and was considered significative when p < 0.05. Long-term mortality and combined events were studied using Kaplan-Meyer curves with median follow-up of 11.21 months. Results: The median age in the younger group was 48 years versus 69 years in the elderly group. In the younger group 26% was ST-myocardial infarction versus 18% in the elderly group. About 7% of younger patients were submitted to coronary bypass surgery and 42% to percutaneous coronary angioplasty versus 12% and 25% in elderly group, respectively. Significant difference was observed between the younger versus elderly groups in deaths (1.5% × 7.5%, p = 0.004), combined events (14.9% × 26.3%, p = 0.02) and killip III/IV (3.7% × 8.3%, p = 0.04). Long-term mortality was 3.7% × 10.2%, p = 0.01). Conclusions: In patients with acute coronary syndromes age was an important predictor factor of mortality and complications. Significative differences in outcomes were observed between the two groups in-hospital and long-term follow-up.