This study examines age-related differences and temporal trends in hospital and long-term survival after acute myocardial infarction (AMI) over a 2-decade-long (1975 to 1995) experience. A total of 8,070 patients with validated AMI hospitalized in all acute care hospitals in the Worcester, Massachusetts, metropolitan area (1990 census population 437,000) were studied over 10 one-year periods between 1975 and 1995. This population included 1,326 patients aged <55 years (16.4%), 1,768 patients aged 55 to 64 years (21.9%), 2,325 patients aged 65 to 74 years (28.8%), 1,880 patients aged 75 to 84 years (23.3%), and 771 patients aged > or = 85 years (9.6%). Compared with patients <55 years, patients 55 to 64 years were 2.2 times more likely to die during hospitalization for AMI, whereas patients 65 to 74, 75 to 84, and > or = 85 years were at 4.2, 7.8, and 10.2 times greater risk of dying, respectively. Similar age disparities in the risk of dying were seen when controlling for additional prognostic factors. Despite the adverse impact of increasing age on hospital survival after AMI, declining in-hospital death rates were seen in each of the age groups under study, with declining magnitude of these trends with advancing age. Among discharged hospital patients, increasing age was related to a significantly poorer long-term prognosis. Trends toward improving long-term prognosis were seen in patients discharged in the mid-1990s compared with those discharged in the mid- to late 1970s for patients aged <85 years. The present results demonstrate the marked impact of advancing age on survival after AMI. Despite the adverse impact of age on prognosis, encouraging trends in prognosis were observed in all age groups, although to a lesser extent in the oldest elderly patients. These findings emphasize the low death rates in middle-aged patients with AMI and the need for targeted secondary prevention efforts in elderly patients with AMI.