Background and aim: The best way to reduce myocardial infarction (MI) is to find its risk factors and prevent or modify them in high-risk populations. This leads to decreasing of its complication and mortality and thus maintenance of productive potential in the societies. Therefore, the aim of this study was to identify MI risk factors in patients referred to Chaharmahal and Bakhtiary province hospitals, 2005.Methods: This case-control study was performed on a total of 247 patients suffering from MI from Chahrmahal and Bakhtiary province during 2005. These patients were assigned as the case and 240 of the other patients as the control group. The patients were compared in the case of predisposing factors to MI. Data were gathered by a questionnaire consisting of four sets of questions: demographic and physiologic variables, Holmes and Rahe Scale, standard activity and standard annual diet. Data were analyzed using regression, Chi-square, Fischer and Odds ratio tests. Results: Base on the results, there was no significant difference between the two groups in the cases of age, sex, education, job and the place of life. In the case and the control, the frequency of high blood pressure, 40.5%, 29.6% (p<0.01, OR=3.68), total cholesterol level: 42.9% and 19.2% (p<0.001, OR=5.22), Diabetes: 29.1%, 12.1% (p<0.001, OR=3.68), smoking: 60.4%,39.6% (p<0.01, OR=1.78), stress: 34.4%, 15.4% p<0.01, OR=2.78), and obesity: 15.6%, 5.4% (p<0.001, OR=2.97), respectively. These are recognized as the main risk factors of the disease in this region.Conclusion: The findings showed that the history of high blood pressure, high cholesterol level, diabetes, smoking, stress and obesity were the main MI risk factors in this area.