BACKGROUND: Although the main risk factors of acute coronary syndrome (ACS) have been previously identified, there is not yet strong and consistent evidence about the ethnical differences of these risk factors. The aim of this study was to identify and compare the distribution of risk factors of ACS among two ethnic groups in northern Iran.METHODS: This cross-sectional study was done on a total of 250 patients (100 Fars and 150 Turkmen ethnics) with ACS admitted in coronary care units (CCU) of medical centers in Gonbad-e Kavus, a city in the Northeast of Iran. The demographic characteristics, clinical parameters and anthropometric indices of patients in two ethnic groups were recorded. In addition, Beacke’s questionnaire and Cohen's scale were used to evaluate and compare the patients’ level of physical activity and perceived stress, respectively.RESULTS: The mean age of the patients was 60.9±11.9 years and they were mostly males (54.8%) and married (84.8%). Findings showed that the prevalence of myocardial infarction in Fars patients was significantly higher than Turkmens (24% versus 15.3%; P=0.04). In addition, there was a significant difference in terms of the history of using opium (P=0.07) and opium sap (P=0.03)‚ socioeconomic status (P=0.009)‚ the place of residence (P=0.001) and type of health insurance services (P=0.001) between two groups. However, the clinical parameters and anthropometric indices and the level of physical activity and perceived stress were not significantly different between two groups (P>0.05).CONCLUSION: This study showed a significant difference in the prevalence and risk factor of ACS in patients with different ethnicity in northern Iran. This finding points to the importance of paying attention to the ethnicity-based difference in ACS prevalence and risk factors, especially in patients who are at high to intermediate risk for ACS, such as Turkmens.KEYWORDS: Acute Coronary Syndrome‚ Risk factors‚ Ethnic groups, Heart Diseases, Iran