In patients with acute myocardial infarction(MI), mortality can be predicted by risk scoring systems, but the impact of therapy recommended by guidelines is poorly documented. The aim of this study was to determine, taking into account the patient’ s condition at admission, to what extent the degree of guideline compliance influences the 1- year survival of patients admitted for acute MI.Methods and results: A 6- month registry was carried out in a geographically limited area, prospectively including all patients with acute MI. A risk score based on initial presentation, and a compliance index based on patient characteristics, type of MI, in-hospital management(including revascularization strategies and use of recommended drugs)were established. Patients were clinically followed at 1 year. A total of 754 patients, 333 ST elevation MI and 421 non-ST elevation MI, were included. The median compliance index(percentage of optimal compliance with guidelines) was 0.66(95% CI 0.5;8.3). One-year mortality rate was 11.5% . By logistic regression, three variables were independently related to mortality: type of MI[OR=2.6(1.5;4.3)], risk score[OR=2.4(1.9;3.1) per additional 10% ], and compliance index[OR=0.8(0.7;0.9) per additional 10% ]. Conclusion: A clear relationship between the extent of guideline implementation,and 1-year mortality was shown and this relationship remained strong after stratification on the risk score at admission and the type of MI. These data emphasize the need for thorough implementation of guidelines to improve the outcome of patients suffering from acute MI. In patients with acute myocardial infarction (MI), mortality can be predicted by risk scoring systems, but the impact of therapy recommended by guidelines is poorly documented. The aim of this study was to determine, taking into account the patient ’s condition at admission , to what extent the degree of guideline compliance influences the 1-year survival of patients admitted for acute MI. Methods and results: A 6-month registry was carried out in a geographically limited area, prospectively including all patients with acute MI. A risk score based on initial presentation, and a compliance index based on patient characteristics, type of MI, in-hospital management (including revascularization strategies and use of recommended drugs) were established. Patients were clinically followed at 1 year. A total of 754 patients, 333 ST elevation MI and 421 non-ST elevation MI, were included. The median compliance index (percentage of optimal compliance with guidelines) was 0.66 (95% CI 0.5; 8.3). One-ye ar mortality rate was 11.5%. By logistic regression, three variables were independently related to mortality: type of MI [OR = 2.6 (1.5; 4.3)], risk score [OR = 2.4 and compliance index [OR = 0.8 (0.7; 0.9) per additional 10%]. Conclusion: A clear relationship between the extent of guideline implementation, and 1-year mortality was shown and this relationship was strong after stratification on the risk score at admission and the type of MI. These data emphasize the need for thorough implementation of guidelines to improve the outcome of patients suffering from acute MI.