OBJECTIVE To evaluate intra-hospital and first year prognosis of the acute myocardial infarction. METHODS Univariate analysis of hospital and late mortalities in 21 characteristics on the evolution of the acute phase of myocardial infarction of patients sequentially admitted in a coronary care unit. METHODS Coronary care unit and out patient clinic of a school hospital. METHODS A group of 213 patients with acute myocardial infarction admitted sequentially in a coronary care unit was studied. METHODS Making use of a computerized information system the following characteristics f the patients were prospectively studied: age, sex, previous history of myocardial infarction, angor, diabetes, hypertension and tabacism, presence of left ventricular dysfunction electrocardiographic localization of the infarction, presence of angor in the acute phase of the infarction, epistenocardic pericarditis, hypertensive reaction, hypotension, sinus tachycardia, sinus bradycardia, supraventricular disrhythmias, ventricular disrhythmias, A-V block, complete right bundle branch block, complete left bundle block and peak of CPK values. Univariate analysis was made between each one of these characteristics and hospitalar and one year mortalities. RESULTS Statistically significant differences were obtained in the hospitalar mortality in the following characteristics: age (p less than 0.001), sex (p less than 0.03), previous history of diabetes (p less than 0.05) and tabagism (p less than 0.005), left ventricular disfunction (p less than 0.0005), hypotension (p less than 0.005), sinus tachycardia (p less than 0.0005), sinus bradycardia (p less than 0.024), A. V. block (p less than 0.004), and peak of CPK (p less than 0.05). Statistically significant differences were found in one year mortality in the following characteristics: age (p less than 0.001), left ventricular disfunction (p less than 0.02), sinus tachycardia (p = 0.0116) and peak of CPK (p less than 0.05). CONCLUSIONS Influence in the hospitalar mortality was demonstrated by the following characteristics of the patients with myocardial infarction: age, sex, previous history of diabetes and tabagism, left ventricular disfunction, infarct size expressed by the peak values of CPK, sinus tachycardia, sinus bradycardia, hypotensive reaction in the acute phase of the myocardial infarction and A-V block. Mortality in the late phase infarction was influenced by age, left ventricular dysfunction, sinus tachycardia and peak values of CPK.