Introduction. Atrial fibrillation ( is considered to be a new 21st century epidemic, which by the end of 2060 shall affect an estimated 18 million people. More than 6 million Europeans suffer from AF, while in the United States AF is the cause of hospitalization of more than one third of the patients with heart rhythm disorders. Aim of the study. Identifying the importance of different risk factors in patients with AF in the development of thromboembolic complications, and assessing the efficacy of the CHA2DS2 VASc score in their prevention. Materials and methods. 100 patients with AF from the Sfa nta Treime Municipal Hospital, the Neurological Institute and the Institute of Cardiology have been surveyed. 2 groups of interest were obtained: patients with ( and without history of stroke ( All clinical and paraclinical collected data has been s tatistically analyzed and compared between the aforementioned groups. Results. Out of the analyzed 100 patients, 52 were women and 48 men. The mean age was 66.6 years. The mean BMI was 28.2 kg/m2. 91% of the patients had congestive heart failure(CHF), 90% suffered from hypertension, 72% of myocardial infarction(MI) and 24% of diabet es (type I/II). Patients had an average CHA2DS2 VASc score of 5, varying between 2 and 9. Only 52% of the patients were under anticoagulation control. 35 have administered aspirin, 32 warfarin, 15 both. Out of the 52 patients who had their INR checked, only 25% had a therapeutic value between 2 3. In the stroke group, 30 were women, 24 were men. 60.9% out of the patients who had manifest stroke consequences were women. 66.7% of the patients in the same group were older than 65 and 75.9% had a BMI 25 k g/m2. 90.7% presented hypertension, 87% CHF, 87% MI, and only 24,1% suffered from diabetes. CHA2DS2 VASc had a better predictability for scores>5 5 60%, 6 63.6%, 7 93.3%, 8 and 9 both 100%). Only 29 of the patients with a history of stroke rec eived anticoagulant treatment, 13 of which administered only aspirin, while 9 both aspirin and warfarin. Better INR values were obtained in patients who have administered both aspirin and warfarin in the first group, compared to their separate administra tion. Conclusions. Female sex was associated with a worse after stroke evolution. Age and overweight were both independent risk factors for stroke prediction. CHF, MI and hypertension as components of the CHA2DS2 VASc score proved to be important risk fac tors, compared to diabetes, which did not. CHA2DS2 VASc had a good stroke predictability rates for patients with a score > Low anticoagulation coverage and a poor adherence to the anticoagulant treatment in patients with AF were the main causes that led to inappropriate stroke prevention.