Atrial fibrillation affects approximately one million persons in the United States, making it the most common cardiac arrhythmia seen in clinical practice. Its prevalence increases with age, and occurs in up to 10% of the population in the eighth decade of life. Unlike coronary heart disease, atrial fibrillation affects men and women approximately equally and, in an increasingly elderly population, will become an increasing burden to the health care system. The management of atrial fibrillation has undergone significant change in recent years. Large randomized controlled trials have shown that anticoagulation markedly reduces the risk of stroke, and a number of new antiarrhythmic agents are available for the restoration and maintenance of sinus rhythm. Furthermore, physicians have become more aware of the potential proarrhythmic side effects of all antiarrhythmic drugs. Finally, new procedures such as radiofrequency ablation of the atrioventricular junction and permanent pacing are playing increasing roles in the management of this arrhythmia. In this review, the identification of underlying causes and/or precipitating factors of atrial fibrillation, methods to control the ventricular response with atrioventricular nodal blocking drugs, the questions of whether restoration of sinus rhythm is a possible or desirable goal and how best to maintain sinus rhythm, should sinus rhythm be restored, and the importance of long-term anticoagulation with warfarin or antiplatelet therapy with aspirin are discussed.