Although the efficacy and safety of left atrial (LA) appendage (LAA) closure in patients with atrial fibrillation (AF) have been well documented in randomized controlled trials and real-world experience, there are limited data in the literature about the impact of LAA closure on diastolic functions. The study aimed to examine the impact of LAA closure on diastolic function and natriuretic peptide levels in patients with AF.Twelve non-valvular AF patients with high risk for developing cardioembolic stroke and contraindications to warfarin underwent LAA occlusion with the WATCHMAN device (Atritech Inc., Plymouth, MN, USA). B-type natriuretic peptide levels and detailed diastolic parameters (mitral inflow velocities, deceleration time (DT), flow propagation velocity (Vp), isovolumetric relaxation time (IVRT), mitral annular e', TE-e', IVRT/TE-e', E/Vp, E/e', pulmonary vein flow parameters consisting of S, D, and S/D) were evaluated at baseline and 45 days after LAA closure.The median age of the patients was 69 (54-78) years and 75% (n: 9) of them were male. All patients completed forty-five days of follow-up. Compared to the baseline values, E/Vp ratio and BNP levels (1.95 (0.94-3.32) vs. 2.37 (1.09-4.46), p= 0.015; 290.0 (90-1271) pg/ml vs. 322.00 (106-1635) pg/ml, p=0.018, respectively) increased, and pulmonary vein S wave and S/D ratio (0.67 (0.33-0.92) vs. 0.38 (0.23-0.91) m/sec, p=0.048; 1.62 (0.86-5.75) vs. 1.33 (0.11-3.35), p=0.019, respectively) decreased after LAA closure.In the present study, we demonstrated that patients with AF have shown impaired diastolic functions and elevated BNP levels after the percutaneous closure of the LAA.