Acute coronary syndromes (ACS) represent the most common cause of morbidity and mortality in the Western world. Relative epidemiologic data for Greece, a Mediterranean country, are sparse. The aim of the study was to determine the incidence and the clinical presentations of ACS. Over a 1-year period we conducted a prospective, population-based survey of ACS cases in an isolated area of northwestern (NW) Greece with 170,000 inhabitants. Every patient living in the study area, aged <80 years, without history of coronary artery disease, who presented with symptoms suspicious for ACS and was hospitalized for at least 24 hours was eligible for inclusion in the study. For sudden cardiac deaths, relative information was obtained from the autopsy report or the physician who documented death. Additional information regarding timing and associated conditions was obtained from relatives. The diagnosis and classification of the studied cases was performed according to World Health Organization and European Society of Cardiology criteria. The authors identified 352 patients (265 men, 87 women, mean age 62.5 +/-10 and 68 +/-9.5 years, respectively) with first-appeared ACS (174 non-ST elevation, 105 ST elevation, 73 sudden cardiac deaths). Fifty-six patients with other forms of ischemic heart disease (stable angina, heart failure, and silent ischemia) were not included in the analysis. Moreover, 154 patients with chest pain and normal appearing EGG at rest, normal values for enzymes (CK, troponin), and negative exercise testing, as well as 77 patients with normal findings from coronary angiography studies, were also excluded. The annual incidence for the age group of 30-79 was 39/10,000 inhabitants (60.6 for men and 19 for women). The incidence of ACS increased with age in both sexes and was higher in men even after the age of 70. About one third of the ACS and half of the sudden cardiac deaths occurred in the age group of 70-79. Only 3 patients were successfully resuscitated. ACS are common in this area of NW Greece and the majority of them present in a form amenable to therapeutic manipulations. Twenty percent of patients died suddenly, and a very small percentage of these were successfully resuscitated. Preventive measures and acute management facilities need to be improved, even in a Mediterranean country where the incidence of ischemic heart disease is relatively lower than in northern European countries.