A community-based study was conducted in metropolitan Baltimore in which secular trends in the in-hospital and long-term prognosis of 935 male and female patients hospitalized with an initial myocardial infarction were examined for the two periods of 1966-1967 and 1971. The in-hospital case fatality rate among males in both periods remained unchanged (19.0% vs 19.0%), whereas there was a decrease over time among women hospitalized in 1966-1967 as compared to those in 1971 (37.2% vs 26.6%) (p less than 0.10). For patients discharged alive from the hospital and followed up for as long as 10 years, no significant differences in overall survival were observed between male patients discharged in 1966-1967 and 1971 or between female patients discharged in these two periods. These findings may reflect the lack of major therapeutic advances in the care of the acute coronary patient between the two study periods and, therefore, support continuing efforts directed at the primary and secondary prevention of the atherosclerotic process.