Atrial fibrillation (AF) directly leads to a cognitive function decline regardless of the cerebrovascular fatal events, but it is unclear whether the sinus rhythm restoration and reducing the AF burden can reduce the rate of this decreasement. Data on the effect of radiofrequency ablation on patients’ cognitive functions are conflicting and need to be studied. The aim of the study was to evaluate the prognostic value of atrial fibrillation radiofrequency catheter ablation on cognitive functions in patients with chronic heart failure with preserved left ventricular ejection fraction. The impact of AF radiofrequency catheter ablation on cognitive function in 136 patients (mean age 59.7 ± 8.6 years) with chronic heart failure with preserved left ventricular ejection fraction and compared with 58 patients in the control group (58.2 ± 8.1 years), which did not perform ablation and continued the tactics of drug antiarrhythmic therapy was investigated. Cognitive function was assessed using the Montreal Cognitive Test (MoCA) at the enrollment stage and 2 years follow-up. Decreased cognitive function was defined as a MoCA test score < 26 points, cognitive impairment < 23 points. Two years after the intervention, there was a positive dynamics (baseline MoCA test — 25,1 ± 2,48, 2-year follow-up — 26,51 ± 2,33, p < 0,001) in the ablation group and negative in the control group (25,47 ± 2,85 and 24,57 ± 3,61, respectively, p < 0,001). Pre-ablation cognitive impairment was significantly associated with improved cognitive function 2 years after AF ablation according to polynomial regression analysis. The obtained data suggest a probable positive effect of AF radiofrequency ablation on cognitive functions in patients with preserved left ventricular ejection fraction.