Amiodarone is an antiarrhythmic agent with unique electrophysiological and pharmacokinetic properties and a wide spectrum of antiarrhythmic activity. Its clinical efficacy is not confined to ventricular arrhythmias but extends to supraventricular arrhythmias including those associated with Wolff-Parkinson-White Syndrome. Though a highly effective drug, amiodarone causes significant side effects. In this article, the electrophysiologic and pharmacokinetic properties, the clinical efficacy, and the adverse effects of amiodarone are reviewed.