BACKGROUND: Direct oral anticoagulants (DOACs) use is complicated by bleeding, especially in the geriatric population. Most studies focus on predicting major bleeding, while clinically relevant non-major bleeding (CRNMB) is no less important for practice. АIM: of the study was to evaluate the ability of clinical factors to predict the risk of CRNMB while taking DOACs in patients with atrial fibrillation (AF) aged 80 years and older. MATERIALS AND METHODS: 367 patients were examined with non-valvular AF aged 80 years and older (median age 84 [82; 88] years) taking DOACs. The main population parameters (gender and age composition of groups, body mass index), risk of ischemic stroke according to the CHA2DS2-VASc scale, risk of bleeding according to the HAS-BLED scale, comorbidity, Charlson comorbidity index, risk factors for chronic non-communicable diseases, number of medications taken, objective examination data, vascular wall stiffness, and laboratory test results were assessed. RESULTS: In univariate analysis, significant risk factors for developing CRNMB with all DOACs were: higher frequency of walking (p=0.022), lower heart rate (p=0.08), and history of gastric and duodenal ulcer (GDU) (odds ratio (OR) 5.34 [95% confidence interval (CI): 2.31; 12], p0.001). As a result of multivariate analysis, a model for predicting CRNMB was developed, with age, type of DOAC, liver disease, acute cerebrovascular accident, history of GDU selected as predictors. The resulting model was characterized by 62.6% [95% CI: 57.4; 67.6] predictive accuracy, 66.5% [95% CI: 59.4; 73.1] sensitivity and 58.2% [95% CI: 50.4; 65.7] specificity. CONCLUSION: The study identified specific modifiable, potentially modifiable, and non-modifiable risk factors for the development of CRNMB in patients with AF over 80 years of age taking DOACs. The results of the study can be used to create an electronic system to support medical decision-making, manage risk factors, and improve the quality of life of the population.