OBJECTIVE: To compare 30-day mortality in patients receiving different types of medication from 1992 to 1997, when no consensual treatment for acute myocardial infarction was available, versus 30-day mortality in patients being treated between 2000 and 2002 after standardization of that treatment was obtained in our service. METHODS: In the first and second study periods, 172 and 143 patients, respectively, admitted with the diagnosis of acute myocardial infarction were retrospectively assessed. Their diagnoses were confirmed, and the following statistical tests were performed: the chi-square test for comparing proportions and the Student t test and the Mann-Whitney test for comparing the means or medians. RESULTS: The analysis showed no difference in regard to white men with a mean age of 61 years in the 2 study periods. In regard to the traditional risk factors, a difference was observed only in the incidence of dyslipidemia (17 and 29%). In regard to the therapeutic strategy adopted, the following was observed: 1) a significant increase in the use of thrombolytic agents (39 and 61.5%), acetylsalicylic acid (70.9 and 96.5%), beta-blockers (34.8 and 67.8%), angiotensin-converting enzyme inhibitors (45.9 and 74.8%), and nitrates (61 and 85.3%); and 2) a significant reduction in the use of calcium channel blockers (16.8 and 5.3%), antiarrhythmics (29.1 and 9.7%), and diuretics (50.6 and 26.6%). The use of inotropic agents did not differ between the study periods (29.6 and 32.1%). The 30-day mortality showed a statistically significant reduction from 22.7 to 10.5%. CONCLUSION: The implementation of standard protocols for the treatment of acute myocardial infarction was accompanied by a significant reduction in the 30-day mortality rate.