Since the development of beta-adrenergic blocking agents over 30 years ago, they have been established as an important therapeutic modality in the treatment of coronary heart disease. This article reviews the role of beta-blockers in the treatment of hypertension, angina, acute myocardial infarction, and heart failure. A number of multicenter studies indicate that beta-blockers have an important effect in decreasing morbidity and mortality in patients with hypertension and appear to have a relatively increased importance in elderly patients with hypertension. Although their long-term effects on the mortality of angina pectoris have not been fully investigated, investigations indicate that, compared with other drugs, beta-adrenergic blocking agents significantly decrease the frequency and duration of angina pectoris. The largest use of these drugs has been examined in the treatment of acute myocardial infarction. Two major trials, the Norwegian Timolol Trial and the Beta Blocker Heart Attack Trial, confirm the long-term benefit in patients following acute myocardial infarction. Their use in heart failure is under close investigation following a series of preliminary studies suggesting they may decrease mortality risk. Although the tolerability of these drugs has been questioned, careful examination of clinical trials indicate that they are relatively well tolerated. These observations emphasize the importance of beta-adrenergic blocking agents in hypertension, angina, and acute myocardial infarction and speak to a wider clinical use of these drugs.