Atrial fibrillation (AF) is the most common tachyarrhythmia in athletes.  Triggers for AF in athletes include atrial ectopy, sports supplements and sympathomimetic drugs.  Substrates for AF in athletes include cardiac (mainly atrial) remodeling, fibrosis and inflammation.  Autonomic activation, electrolyte abnormalities, and acid reflux disease serve as modulators of AF.  Evaluation of AF in athletes consists of classification of the type of AF and assessment for underlying causes and precipitating factors.  Management of AF in athletes involve identification and modification of triggers and reductions of physical activity.  Rate control strategies may reduce athletic efficiency.  Anti-arrhythmic drug therapy of AF in athletes has not been extensively studied.  Anticoagulation recommendations are similar to those for non-athletes with AF.  Preliminary studies suggest that radiofrequency ablation techniques may be applied successfully in athletes with AF.