We describe the mortality during the subsequent 5 years after development of acute myocardial infarction prior to and after the introduction of a more widespread use of thrombolytic agents and aspirin in the community of Göteborg. During period I, 4% received thrombolysis as compared with 32% during period II (p < 0.0001). The corresponding figures for prescription of aspirin at discharge were 14 and 84%, respectively (p < 0.0001). The overall 5-year mortality was 48% during period I and 46% during period II (p = 0.09). However, the age-adjusted mortality during period II was significantly reduced (risk ratio 0.86; 95% confidence interval 0.78-0.95; p = 0. 004). There was no significant interaction between improvement in survival and sex or any other parameter reflecting patients' clinical history.