Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide, and it is a very frequent cause of increased morbidity and mortality in adults. This arrhythmia favors the formation of thrombi, which can lead to systemic embolism, such as ischemic stroke.To identify patients with thromboembolic risk, the most used score is the CHA2DS2VASC, which takes the following factors in consideration: heart failure, arterial hypertension, age, diabetes, previous stroke, vascular disease, and sex. It is worth emphasizing that this score does not take renal function or dialysis treatment into consideration.Oral anticoagulation (OAC) is indicated in the majority of patients to decrease embolic events; however, it increases hemorrhagic events. Therefore, we must assess the patient's individual risk of both thromboembolic and hemorrhagic events, when indicating OAC. The most used score for assessing the risk of bleeding is the HAS-BLED, which takes the following factors in consideration: arterial hypertension, renal and hepatic dysfunction, previous stroke, bleeding, international normalized ratio (INR) lability, age, and drug and alcohol use. In this score, renal dysfunction receives 1 point for risk of bleeding.