Objective: Atrial fibrillation (AF) is the most prevalent sustained cardiac arrhytmia and constitutes a major public health problem. Patients with AF often have a variety of co-morbidities and need frequent hospitalizations. The present retrospective cohort study used medical claims data to evaluate the rates of hospitalization in patients with AF in Turkey. Methods: We analyzed the records of patients over the age 18 who had the diagnosis of non-valvular atrial fibrillation (AF) according to ICD-10 code I48 from a claims and utilization management system called MEDULA which processes claims for all health insurance funds in Turkey since 2007. Covering close to 100 % of the population, MEDULA is comprised of pharmacy, inpatient, outpatient and laboratory claims and covers 23,500 pharmacies, 20,000 general practitioners, 850 government hospitals, 60 university hospitals and 500 private hospitals. In this study we have used completely anonymized data Results: Of an eligible study population of 402674 patients with AF (mean age 68,3 years, 44,2% men), 102334 patients (25,4%) were hospitalized, 68951 (17,1%) were rehospitalized. Seventy seven percent of females and sixty seven percent of males older than 65 years were hospitalized. The most common admission diagnoses were congestive heart failure (47,1%), ischemic stroke or transient ischemic attack (21,1%), gastrointestinal bleeding (5%), hemorrhagic stroke (1,5%) and thromboemboli (1,4%). Twenty nine percent of coumadin users, 27,2% of aspirin users, 23,9% klopidogrel users 23,3 % of clopidogrel+aspirin users and 21,1% of none user patients were hospitalized. When we performed time-to event analysis we found that the earliest hospitalizations were for coumadin users due to bleeding (p<0.001). Conclusions: Elderly patients, especially females, with AF underwent frequent hospitalization both for CV and non-CV causes. Anticoagulant therapy with warfarin did not reduce hospitalization rate as a result of increased hospitalizations due to bleeding complications. Therefore, measures that lower bleedings and inpatient readmission rates may reduce the increasing cost of treating patients with AF and reduce the burden on health economics.