Background and Aim: Recently, a clear evidence suggests that nonalcoholic fatty liver disease (NAFLD) is associated with an increased risk of incident atrial fibrillation (AF). Yet, the underlying pathogenesis is speculative. Thereby, we aimed to investi- gate the hypothesis that, interatrial thickness (IAST) and left atrial stiffness (LASt) might have mechanistic links between NAFLD and AF. Methods: Echocardiography and speckle-tracking assessment of left atrial function, transient elastography (TE) of the liver, basal ECG, and Holter monitoring were per- formed in 180 patients with (NAFLD) and 80 subjects without NAFLD. Results: Patients with NAFLD had higher values of IAST (P < 0.001), LASt (<0.001), and E/e′ ratio (<0.003) compared with controls. IAST was correlated with LASt (r = 0.413; P < 0.001). 15.6% of patients with NAFLD had AF. More so, patients with increased IAST/LASt had a higher incidence of AF (25%) vs 3.8% in those with normal IAST/LASt. The LASt and IAST increased significantly in those with AF compared with those with- out (P < 0.001). Patients who experienced AF had higher values (P < 0.01) of TE (kPa). The degree of liver stiffness TE (kPa) was correlated with both IAST and LASt (r = 461, r = 0.535; P < 0.001). Furthermore, multivariate regression analysis showed that LASt and IAST were independent predictors of incident AF in subjects with NAFLD. Conclusions: Our data suggest that increased IAST and LASt index are independently as- sociated with incident atrial fibrillation in patients with NAFLD. Increased IAST and LASt index might provide mechanistic links between NAFLD and incident atrial fibrillation.