OBJECTIVE: An increased cardiovascular mortality and morbidity has been widely reported in patients with atrial fibrillation (AF). In this study, a subanalysis of the AntiThrombotic Agents Atrial Fibrillation (ATA‐AF) is performed with the aim to evaluate estimated glomerular filtration rate (eGFR) as an independent prognostic marker of cardiovascular mortality and morbidity in patients with AF. METHODS AND RESULTS: The ATA‐AF study enrolled 7148 patients with AF, in 360 Italian centers. The eGFR was calculated from data reported in patient notes or hospital database. This post‐hoc analysis included 1097 AF patients with eGFR data available and 1‐year clinical follow‐up. The endpoint was assessed as cardiovascular mortality and/or hospital admission for cardiovascular causes at follow‐up. Patients were also divided in two groups according to the eGFR (