Introduction: The purpose of this study was to assess the renal function in patients with nonvalvular atrial fibrillation and acute stroke and its relationship with survival and functional outcome. Methods: We have included 99 patients with atrial fibrillation admitted for acute stroke. At admission demographic characteristics (age, sex), blood pressure, heart rate, serum creatinine were recorded. Estimated glomerular fi ltration rate (eGFR) was calculated (CKDEPI), the patients were divided into 2 groups: group 1 (n = 52) – eGFR ≤ 60 ml/minute/1.73 m2 and group 2 (n = 47) – eGFR > 60 ml/minute/1.73 m2. CHADsVASc and HASBLED scores were calculated. Functional disability was assessed using the Rankin scale; in-hospital deaths were recorded. Statistics: mean ± SD, Student’s t test and Fisher’s exact test, univariate analysis. Results: Mean age was 72 ± 8 years in group 1 and 70 ± 8 years in group 2. Blood pressure values and heart rate at admission were similar in both groups. CHADsVASc score was 4.6 ± 1.2 in group 1 and 4.3 ± 1.1 in group 2, while HASBLED score was 2.8 ± 1.04 in group 1 and 2.2 ± 0.7 in group 2. Rankin scale >3 was more frequent in group 1-32 P (61%) compared to group 2 – 19 P (40%), p = 0.04. During hospitalization there were 22 deaths,14 in group 1 and 8 in group 2 (p = 0.3). At univariate analysis the negative functional outcome was correlated with low eGFR (OR = 2.35 – p = 0.04) and marginally signifi cant with age (OR = 1.04 – p = 0.09). Mortality was correlated with the HASBLED score (OR = 2.41 – p = 0.01), systolic blood pressure (OR = 0.97 – p = 0.04) and heart rate at admission (OR = 1.02 – p = 0.01). Conclusions: In patients with atrial fibrillation and acute stroke renal dysfunction is associated with worse functional outcome, while a higher HASBLED score and higher heart rate at admission are associated with poor survival.