The new antiarrhythmic drug dronedarone (SR 33 589) is a benzofuran derivative structurally similar to amiodarone, however is noniodinated. The additional methansulfonylgroup renders it less lipophilic, with a substantially shorter half-life, compared to the parent compound. The electrophysiological properties of both agents are similar with inhibition of Na+, K+, and Ca++ currents (all Vaughan-Williams classes). The agent has been evaluated in a large clinical study program. The daily dose of dronedarone 800 mg has been shown (DAFNE) to be effective and well tolerated. In two design-identical randomised clinical trials (EURIDIS and ADONIS trial) the efficacy of dronedarone to maintain sinus rhythm in patients with chronic atrial fibrillation/flutter was shown to be clearly superior to placebo. The ERATO study showed the rate control properties of dronedarone. In the ATHENA morbidity/mortality study, the combined endpoint death or hospitalisation due to cardiovascular events occurred significantly less often in the dronedarone group compared to the placebo group. Particularly due to its beneficial effects on clinical outcomes such as cardiovascular hospitalizations and death in the context of high tolerability dronedarone appears to be a promising new antiarrhythmic compound.