BackgroundImproving use of anticoagulants in atrial fibrillation (AF) patients in primary care has proved challenging. Anticoagulants are often prescribed by primary care physicians in the long term. Suboptimal anticoagulant use may be partly due to physicians' non-prescribing. One potential way of targeting physician prescribing behavior is “audit & feedback”. The documented use of audit and feedback in research aimed at increasing use of anticoagulants in primary care is limited. The objective was to test if an audit & feedback intervention aimed at directors in primary care centers could increase the use of anticoagulants in patients with AF. MethodsDatabase generated quality reports with primary care center specific data on recommended medication use in their patients with previous stroke or atrial fibrillation were sent to intervention centers. Results94 centers received the intervention, 102 centers were controls. 31,477 patients in total were included. Use of anticoagulants in all primary care centers increased from 76% before to 82% after the intervention. Patients in intervention centers were more likely than patients in control centers to use anticoagulants after the intervention, adjusted odds ratio increasing slightly from 1.04 (95%, CI, 0.98–1.10) before to 1.08 (95% CI, 1.02–1.15) after the intervention. ConclusionsAn audit & feedback intervention with quality reports in primary care had only a small effect on anticoagulant use in patients with AF. A combined and more complex intervention may have a greater effect in improving anticoagulation use.