OBJECTIVES: To present Brazilian data on atrial fibrillation (AF) and perform a cost analysis of events related to this disease. METHODS: AF is an important risk factor for stroke and ischemic heart failure (HF) and death. It is estimated that in Brazil there are around 1.5 million patients with AF and that this population is correlated with the age pyramid. The prevalence of AF in the general population is estimated between 0.4% and 1%, increasing substantially with age. Among the strokes 20% are related to AF and 85% of these strokes are of ischemic origin and 15% of hemorrhagic origin. The stroke mortality in Brazil is 20.5 per 100,000. A panel of experts examined the resources related to the treatment of events related to AF. The panel was conducted through a questionnaire, where the experts listed all procedures, tests, drugs and materials used in every event. Unit costs for drugs and material were obtained from acquisition lists (BPS and SIMPRO magazine, respectively), hospitalization, exam and procedure costs were extracted from a public reimbursement database (SIGTAP). RESULTS: From the expert panel performed, the cost of events were: fatal ischemic stroke (IS) 11,810BRL (7,398USD), non-fatal IS without disability 2,812BRL (1,761USD), non-fatal IS with moderate disability 4,470BRL (2,800USD), non-fatal IS with total disability 6,280BRL (3,934USD), embolism 11,810BRL (7,398 USD), transient ischemic attack 1,808BRL (1,133USD), fatal intracranial hemorrhage 15,572BRL (9,754USD), fatal hemorrhagic stroke (HE) 23,260BRL (14,570USD), non-fatal HE without disability 2,812BRL (1,761USD), non-fatal HE with moderate disability 4,470BRL (2,800USD), non-fatal HE with total disability 6,280BRL (3,934USD), fatal extracranial hemorrhage 1,018BRL (638USD), minor bleed 19BRL (12USD), fatal acute myocardial infarction (AMI) 15,530BRL (9,728USD) and non-fatal AMI 16,852BRL (10,556USD).    CONCLUSIONS: Costs of events related to AF were significant, which underscores the importance of preventing it. Further, it is known that as the population ages the prevalence of events increases.