To evaluate the potential differences in risk factors' profile for in-hospital mortality and up to 1-year prognosis, between younger and older patients with first acute coronary syndromes (ACS).From October 2003 to September 2004, 1323 patients with first ACS event from 6 urban and rural Greek hospitals were enrolled into the study, classified as those < 65 years and ≥ 65 years old. Multiple logistic regression analysis was used to evaluate the association between socio-demographic, lifestyle, clinical characteristics and the disease prognosis for one year after discharge.The men-to-women ratio was 8.5-to-1.5 for those < 65 years, whereas, it was 6.6-to-3.4 for those above 65 years (p < 0.001). In-hospital deaths and recurrent event within 30-days was higher among older patients (p < 0.001). After the period of 6-months, the event-rate was higher among the younger patients (p < 0.001). Current smoking was associated with increased risk of 1-month recurrent events, in patients < 65 years (p < 0.05). Myocardial infarction and history of diabetes were associated with increased risk in older patients (p < 0.1).Age-specific identification of the risk factors for recurrent events may have important clinical and public health implications and lead to the development of more effective risk reduction strategies.