The profile of Czech AF 2012 is an epidemiological survey conducted by 197 Czech internal medicine and cardiology specialists who aimed to provide a comprehensive view of patients with non-valvular atrial fibrillation and their treatment in the Czech Republic. Each special- ist had to include 5 consecutive patients. It involved 982 patients with an average age of 69.9 ± 10.04 years. The population of men was slightly higher (n = 543,55.3%),especially in the under 65 years age group; women were the majority in the age group above 75 years (44.3% of men, 55.7% of women). One quarter (25.1%) of patients were diagnosed with atrial fibrillation for less than 2 years; 23.2% for 2-5 years; 13.5% for 6-10 years, and 8.6% for more than 10 years. 20.7% of patients had paroxysmal atrial fibrillation; 58.5% indicated permanent atrial fibrillation, i.e. lasting more than one year. 58.7% of patients received medication to regulate heart rhythm; 44.0% had another antiarrhythmic medication. 13.8% of patients used their medication once a day; 55.1% twice a day, and 29.6% three times a day. 38.7% of patients were after cardioversion, 7.9% were after ablation. 91.5% of patients received warfarin alone or as dual (1.4%) therapy. Only 8.7% of patients had medium or severe kidney impairment. Only 7.5% of patients used acetylsalicylic acid, 0.2% used dual antiplatelet treatment. Only 3.0% of patients had CHADS2 = 0; 55.8% were at a medium risk (CHADS2 = 1-2), and 41.2% at a high risk (CHADS2 > 2). 22.1% had one associated condition; 27.5% had two associated conditions; 19.8% had three associated conditions; 28.7% had four or more associated conditions; and only 2.0% indicated no associated condition or gave no answer. The most common associated condition was hypertension (90.2%), followed by ischemic heart disease (50.9%) and diabetes mellitus (41.8%). 95 patients (9.7%) had a history of embolism while receiving antithrombotic therapy. 102 patients (10.4%) had a clinically significant bleeding event while on antithrombotic therapy, 51 patients needed hospitalization. The average frequency of INR measurements was 10.2 per year (10.4 by cardiologists, 10.1 by internal medicine specialists). 61.6% were within the INR therapeutic range of 2-3. Conclusion: Atrial fibrillation patients are commonly elderly, polymorbid and high-risk patients on a pharmacological medication two to three times a day. INR monitoring was close to the level described in large international studies, almost 2/3 of patients were within the therapeutic range.