Beta-adrenergic blocking agents have been widely used in ischemic heart disease. They have achieved their greatest benefit in the secondary prevention of recurrent events in patients following acute myocardial infarction (MI). This is a review of the major clinical investigations exploring the effects of beta-adrenergic blocking agents in patients following acute MI and in a variety of patient subsets. These data indicate that the routine use of beta-adrenergic blocking agents in postinfarction patients results in a 25% to 35% decrease in mortality and has increased relative and absolute benefit in patients with ventricular ectopy and left ventricular dysfunction. The adverse effects of beta-adrenergic blocking agents are discussed which indicate that these drugs are well tolerated with little or no side effects. This review supports the observation that beta-adrenergic blocking agents have an important role in the treatment of patients following an acute MI, with the exclusion of those with chronic lung disease and severe left ventricular dysfunction.