Context: Despite evidence from randomized trials that, compared with early thrombolysis, primary percutaneous transluminal coronary angioplasty (PTCA) after acute myocardial infarction (AMI) reduces mortality in middle- aged adults, whether elderly patients with AMI are more likely to benefit from PTCA or early thrombolysis is not known. Objective: To determine survival after primary PTCA vs thrombolysis in elderly patients. Design: The Cooperative Cardiovascular Project, a retrospective cohort study using data from medical charts and administrative files. Setting: Acute care hospitals in the United States. Patients: A total of 20 683 Medicare beneficiaries, who arrived within 12 hours of the onset of symptoms, were admitted between January 1994 and February 1996 with a principal discharge diagnosis of AMI, and were eligible for reperfusion therapy. Main Outcome Measures: Thirty-day and 1-year survival. Results: A total of 80 356 eligible patients had an AMI at hospital arrival and met the inclusion criteria, of whom 23.2% received thrombolysis and 2.5% underwent primary PTCA within 6 hours of hospital arrival. Patients undergoing primary PTCA had lower 30-day (8.7% vs 11.9%, P = .001) and 1-year mortality (14.4% vs 17.6%, P = .001). After adjusting for baseline cardiac risk factors and admission and hospital characteristics, primary PTCA was associated with improved 30-day (hazard ratio [HR] of death, 0.74; 95% confidence interval [CI], 0.63-0.88) and 1-year (HR, 0.88; 95% CI, 0.73-0.94) survival. The benefits of primary coronary angioplasty persisted when stratified by hospitals' AMI volume and the presence of on-site angiography. In patients classified as ideal for reperfusion therapy, the mortality benefit of primary PTCA was not significant at 1-year follow-up (HR, 0.92; 95% CI, 0.78-1.08). Conclusion: In elderly patients who present with AMI, primary PTCA is associated with modestly lower short- and long- term mortality rates. In the subgroup of patients who were classified as ideal for reperfusion therapy, the observed benefit of primary PTCA was no longer significant.