<p class="abstract"><strong>Background:</strong> Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with cognitive impairment and dementia. Cognitive and functional impairments have been neglected in clinical trials with patients affected by AF. Dabigatran is a new drug, which can offer a more stable long-term anticoagulant therapy compared to warfarin. This advantage could be associated with a minor incidence of cognitive and functional decline. The objective of the study is to evaluate the effects of dabigatran compared with warfarin on cognitive and functional impairments, thrombin production, bleeding occurrence and cerebrovascular complications in elderly patients with AF.</p><p class="abstract"><strong>Methods:</strong> A randomized, prospective parallel, two-center, active-controlled trial will be performed in a sample of 200 patients with AF randomly designated to take dabigatran (150 mg twice daily) or warfarin (once daily, dose controlled by INR between 2 and 3). After one and two years, subjects will be assessed considering cognitive outcomes. Additionally, patients will be submitted to brain magnetic resonance imaging (MRI) at the beginning and ending of study to identify possible cerebrovascular events, as well as carotid ultrasonography to search for atherosclerotic disease.</p><strong>Conclusions:</strong> The GIRAF study expects to provide data about prevention of cognitive and functional impairments among patients on anticoagulant therapy for AF, and to explore new concepts on potential prevention of cognitive decline and benefits for AF patients and their relatives.