Stroke is a serious complication associated with atrial fibrillation, but the risk can vary with clinical characteristics of individual patients. CHADS2 score is the most commonly used stratification scheme because of its simplicity. However, the predictive value for ischemic stroke has been limited in patients at "low and intermediate risk". CHA2DS2-VASc score, which extends CHADS2 scheme by considering additional stroke risk factors, has been recommended to identify "truly low risk" patients who may not need any antithrombotic treatment. This new scheme could improve decision-making for thromboprophylaxis in patients with atrial fibrillation.