Objective Atrial fibrillation (AF) is a common arrhythmia in clinical practice. AF fulfils many of the criteria for a screening programme. No data about the prevalence of AF in non-hospitalized patients are available in Belgium. The aim of the study was to assess feasibility and effectiveness of a nationwide-organized voluntary screening programme in the general population in Belgium. Methods A total of 13.564 participants were screened, of whom 10,758 were older than 40 years (GSP group). Participants filled in stroke risk stratification questionnaires (CHADS2 and CHA2DS2-VASc). A one-lead electrocardiogram was performed. Results 228 participants had AF at the time of screening (AF group), with 125 women and 103 men (i.e. 1.9% and 2.6% of total women and men), representing a prevalence of 2.2% (95% Cl 1.3% and 3.0%) of the screened population. Age of the AF group was 67 +/- 12 y (range 40-87 y). Using the CHADS2-score, 58% of participants with a positive AF screening had a high risk score, and 21% had an intermediate risk score. Using the CHA2DS2-VASc-score, 72% of the participants had a high risk score, and 21% had an intermediate risk score. Conclusion AF was present in 2.2% of the respondents. At least 60% of AF group had an increased risk for thrombo-embolism. Although substantial methodological issues limit the exact interpretation of these results, the present study shows that a volunatry screening programme with a simple screening protocol is able to detect an important number of patients with previously undetected AF.