The degree of electroanatomical remodeling of the left atrial (LA) affects the clinical outcome after rhythm control of atrial fibrillation (AF). Our hypothesis was that plasma concentrations of transforming growth factor (TGF)-β and tissue inhibitor of metalloproteinase (TIMP)-1 reflect LA voltage and structural remodeling in patients with non-valvular AF. In the study, 242 patients (male 79.4%, 55.1±11.0 years old) with AF (155 paroxysmal AF, 87 persistent AF) underwent catheter ablation. Pre-ablation plasma concentrations of TGF-β and TIMP-1 and the degree of electroanatomical remodeling quantified by LA voltage map (NavX) and 3D-CT were evaluated. The mean LA voltage and volume were compared in patients with high TGF-β (≥ 10.0 ng/ml, H-TGF) vs. low TGF-β (< 10.0 ng/ml, L-TGF) and high TIMP-1 (≥ 1.1 ng/ml, H-TIMP) vs. low TIMP-1 (< 1.1 ng/ml, L-TIMP). Patients with H-TGF had lower mean LA voltage (P= 0.014) and greater LA volume (P= 0.022), particularly, posterior venous LA volume (P= 0.005) than those with L-TGF. In patients with H-TIMP, the mean LA voltage (P= 0.019) was lower than those with L-TIMP. LA volume was significantly higher (P< 0.001) in patients with ejection fraction≤ 58% than those with> 58%. In patients with non-valvular AF, high plasma concentrations TGF-β and TIMP-1 and low ejection fraction were closely related with electroanatomical remodeling of LA.(Circ J 2011; 75: 557-564)