Beta-blockers are effective antiarryhthmic agents for certain types of supraventricular and ventricular arrhythmias. They are able to prevent arrhythmias associated with sympathetic hyperactivity, suppress automaticity, and slow conduction in myocardial tissue with predominant slow-response activity. In animal experiments, beta-blockers have been shown to exert pronounced antifibrillatory effects following occlusion of a main coronary artery. This effectiveness may be the basis for the improved survival of patients with chronic coronary artery disease under long-term beta-blockade. Side effects are often dose-related; the optimal and minimal effective doses of the beta-blocker are critical in limiting adverse effects. As conventional antiarrhythmic agents have not been shown to reduce the risk of mortality in postmyocardial infarction patients, a broader application of beta-blockers as antiarrhythmic agents within the future, possibly in combination with class I or III drugs, seems conceivable.