The beneficial impact of β blockade after an acute myocardial infarction (AMI) is clear, but β-adrenergic blockers differ in multiple characteristics, including lipophilicity and selectivity. The impact of these factors on the effects of β blockade is unknown. We therefore compared the effects of different β blockers on mortality after AMI. Charts of 201,752 patients with AMI were abstracted by the Cooperative Cardiovascular Project, a quality assurance program sponsored by the Health Care Financing Administration. Of the 69,338 patients prescribed β blockers, we compared mortality of patients receiving different β-adrenergic blockers using the Cox proportional-hazards model accounting for multiple factors that might influence survival. The mortality rates of the 2 selective agents, metoprolol and atenolol, were virtually identical (13.5% and 13.4% 2-year mortality, respectively). Compared with metoprolol, patients discharged on propranolol had a slightly increased mortality (15.9% 2-year mortality), which may be related to undetected differences at baseline. Survival with all of the drugs was superior to the 23.9% 2-year mortality seen in patients not receiving β blockers. Beta blockade overall was associated with a 40% improvement in survival. Although the use of β blockade after AMI has major prognostic importance, the present study suggests that the specific β blocker chosen will have little influence on mortality.