- There are few studies of atrial fibrillation (AF) outside of North America or Europe. The aim of the present study was to assess the prevalence, incidence, management and outcomes of patients with new atrial fibrillation, in a large contemporary cohort (2004-2012) of adult patients. The Clalit Health Services (CHS) computerized database of 2 420 000 adults, includes data of community clinic visits, hospital discharge records, medical diagnoses, medications, medical interventions, and laboratory test results. The prevalence of AF on January 1, 2004 was 71 644 (3%). Prevalence and incidence of AF increased with age and was higher in men versus women. During the study period (2004-2012) 98 811 patients developed new non-valvular AF (mean age -72, 50% women, 46% with cardiovascular disease, 6% with prior stroke). The rate of persistent warfarin use (dispensed for >3 months in a calendar year) was low (25.7%) and it increased with increasing stroke risk score. Individual Time in Therapeutic Range (TTR) among warfarin users was 42%. The incidence rate of ischemic stroke and death increased with age. The rate of stroke increased from 2 per 1000 person years in patients with CHA2DS2_VASC SCORE of 0, to 58 per 1000 person years in those with a score of 9. In the present study the prevalence and incidence of AF, stroke, and death were comparable to those reported in Europe and North America. The low use of anticoagulation calls for measures to increase adherence to current treatment recommendations in order to improve outcomes. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.