Influence of left atrial wall thickness on outcome of catheter ablation for atrial fibrillation (AF) is unclear. Overall, 213 patients with AF (128 paroxysmal and 85 persistent) received ablation. We measured the wall thickness of 16 and 19 areas in the pulmonary vein antrum (PVWT) and left atrial body (LAWT), respectively. Coefficient of variation of wall thickness (CV-WT) was calculated to assess heterogeneity in the left atrial wall thickness. In patients with paroxysmal AF, maximum PVWT, mean PVWT, maximum LAWT, and CV-WT were higher in AF recurrent group than in AF-free group (maximum PVWT, 2.85 ± 0.52 vs. 2.50 ± 0.45 mm, P = 0.003; mean PVWT, 1.59 ± 0.13 vs. 1.50 ± 0.15 mm, P = 0.018; maximum LAWT, 3.85 ± 0.77 vs. 3.41 ± 0.61 mm, P = 0.005; CV-WT, 0.34 ± 0.06 vs. 0.32 ± 0.05, P = 0.039). In patients with persistent AF, maximum PVWT, mean PVWT, maximum LAWT, mean LAWT, and CV-WT were higher in the AF-recurrent group than in the AF-free group (maximum PVWT, 2.52 ± 0.36 vs. 2.31 ± 0.36 mm, P = 0.031; mean PVWT, 1.53 ± 0.12 vs. 1.45 ± 0.14 mm, P = 0.036; maximum LAWT, 3.68 ± 0.75 vs. 3.11 ± 0.50 mm, P < 0.001; mean LAWT, 2.34 ± 0.35 vs. 2.13 ± 0.21 mm, P = 0.002; CV-WT, 0.35 ± 0.06 vs. 0.31 ± 0.05, P = 0.005). Thick and heterogeneous left atrial wall contributes to AF recurrence after ablation.