Beta-Adrenergic blocking drugs, by occupying beta receptors without stimulating adenylate cyclase, interfere with the physiologic responses mediated by the sympathetic nervous system. This property has led to their application in the cardiovascular disorders on which sympathetic tone either underlies or contributes to the pathogenesis of the process. Lipid solubility, selective beta-receptor blockade, and intrinsic sympathomimetic activity are three additional characteristics of beta blockers that modify the pharmacodynamics and pharmacologic effects of each agent. As the role of the sympathetic nervous system in the pathogenesis of heart disease is better defined, the development of beta blockers with particular pharmacologic profiles and fewer side effects may provide more specific treatment.