Atrial fibrillation is the most sustained cardiac arrhythmia, occuring in 1-2% of the general population.Its prevalence is estimated to at least double in the next 50 years as the population ages.Atrial fibrillation confers a 5-fold risk of stroke, and one in five of all strokes is attributed to this arrhythmia.Atrial fibrillation is associated with increased rates of death, stroke and other thrombo-embolic events, heart failure and hospitalizations, degraded quality of life,reduced exercise capacity, and left ventricular dysfunction.Ischemic strokes in association with atrial fibrillation can be fatal, and those patients who survive are left more disabled by their stroke and more likely to suffer a recurrence than patients with other causes of strokes.The risk of death from AF-related stroke is doubled and the cost of care is increased 1.5 fold.In atria fibrillation, a risk stratification scheme should be used as an initial, rapide, and easy-to-remember means of assessing stroke risk.The CHADS2 score was the most used score.Inpatients with a CHADS2 score > or equal to 2, chronic anticoagulation was recommended.A new approach to arterial thrombopylaxis in patients with atrial fibrillation has recently been developed : the CHA2DS2-VASc.This score takes into account additional risk factors that may influence a decision whether or not to anticoagulate, i.e vascular disease and female sex.Also, an age of more than 75 is now heavier in the risk stratification.Vitamin K antagonists have been the only oral anticoagulant treatment for decades.Recently, several new anticoagulants drugs, oral direct thrombin inhibitors and oral factors Xa inhibitors, have been developped for stroke prevention in atrial fibrillation.In the next future the advantages of these drugs and the improvement in the management of atrial fibrillation will probably be observed.