Atrial fibrillation (AF) is the most common sustained arrhythmia in adults. It is a significant public health problem in the United States where it affects 2.2 million Americans and almost 10% of the population older than 80 years. It should be emphasized that the prevalence of AF increases with advancing age and with worsening cardiac function. AF is an independent risk factor for death and greatly increases the risk for embolic stroke. In addition, this arrhythmia can be associated with hemodynamic instability, tachycardia-induced cardiomyopathy, and systemic embolism. The management of atrial fibrillation today is directed toward the prevention of thromboembolism, control of the ventricular rate and conversion to sinus rhythm. It is the purpose of this review to summarize the most recent information about the clinical implications and treatment of this common rhythm disorder.