DL-Sotalol is a unique antiarrhythmic agent combining potent beta-blocking properties with the propensity to prolong cardiac repolarization in all myocardial tissues. Its beta-blocker-associated negative inotropic effects are attenuated by its action potential-lengthening effect. The drug has an elimination half-life of 10-15 h. Sotalol's major electrophysiologic profile constitutes the summed effects of beta-blockade and prolonged repolarization. It exerts a potent antifibrillatory action modulated by its antiadrenergic effects. The effectiveness and tolerance of sotalol in a variety of atrial and ventricular dysrhythmias is reviewed in the present article.