Dronedarone (SR 33589; N,N-dibutyl-3-[4-([2-butyl-5-methylsulphonamido] benzofuran-3-yl-carbonyl) phenoxy]propylamine) is a new synthetic noniodinated derivative of amiodarone that is currently undergoing phase III clinical trials. It demonstrates electrophysiologic patterns similar to amiodarone and shows equivalent efficacy in preventing or converting various ventricular and atrial arrhythmias in laboratory animals. Two phase III trials demonstrated that dronedarone is safe and effective for the maintenance of normal sinus rhythm in patients with atrial fibrillation or atrial flutter. Dronedarone at the dose of 400 mg twice daily was effective in preventing both symptomatic and asymptomatic recurrences of atrial fibrillation or atrial flutter and had a safety profile similar to that of placebo. Further studies are needed to determine the long-term effectiveness and safety of dronedarone in various groups of patients with atrial fibrillation. Other clinical applications of this novel antiarrhythmic drug need to be determined in future clinical trials.