Patients with atrial fibrillation (AF) at risk of stroke are not always anticoagulated with vitamin K antagonists (VKA) despite lack of contraindication. Dabigatran, an oral direct thrombin inhibitor, is a new option with proven safety and effectiveness in these patients. The advantages of dabigatran are its more predictable response, obviating coagulation monitoring and possible lower frequency of bleedings. Its drawbacks are cost, lack of antidote and long-term data, frequency of dyspepsia and the twice daily dosage.