Aim To study true prevalence of atrial fibrillation (AF) in a representative sample from the European part of the Russian Federation; to describe characteristics of patients with AF; and to provide the frequency of anticoagulant treatment.Material and methods Cross-sectional data of the EPOCH epidemiological study (2017) were used. Data were collected in 8 constituent entities of the Russian Federation; the sample size was 11 453 people. The sample included all respondents who had given their consent for participation and were older than 10 years. Statistical tests were performed in the R system for statistical data analysis.Results The prevalence of AF in the representative sample from the European part of the Russian Federation was 2.04 %. The AF prevalence increased with age and reached a maximum value of 9.6% in the age group of 80 to 89 years. The AF prevalence among females was 1.5 times higher than among men. With age standardization, the AF prevalence was 18.95 and 21.33 per 1,000 people for men and women, respectively. The AF prevalence increased in the presence of concurrent cardiovascular diseases (CVDs) or diabetes mellitus as well as with an increased number of comorbidities in the same person and reached 70.3 and 60.0 % in patients with 4 and 5 comorbidities, respectively. Patients with AF had a greater number of comorbidities and higher CHA2DS2VASc scores (5.0 vs. 2.0, p<0.001) compared to patients with CVDs without AF. Only 22.6 % of patients with CVD and AF took anticoagulants. Only 23.9% of patients with absolute indications for the anticoagulant treatment received anticoagulants.Conclusion The AF prevalence in the European part of the Russian Federation was 2.04 %; it increased with age and in patients with concurrent CVDs or diabetes mellitus. Most of AF patients (93.2 %) required a mandatory treatment with oral anticoagulants.