Background: N-terminal brain natriuretic peptide (NT-proBNP) are elevated in patients with atrial fibrillation (AF). The objective of this study was to evaluate NT pro-BNP level before catheter ablation could predict the recurrence after catheter ablation of AF Methods: Eighty-one consecutive patients with AF (paroxysmal n=54, persistent n=27) were enrolled in this study. NT-proBNP was measured before catheter ablation. All patients underwent pulmonary vein ablation. The primary endpoint was recurrence of AF at 3 months follow-up. Results: Fifty eight (71.6%) patients had sinus rhythm without medication and twenty Three (28.4%) patients had recurrence of AF at 3 months follow-up. Median plasma NT-proBNP concentrations were significantly higher in patients with recurrence than those with sinus maintenance (386.6 vs.143.6 pg/ml , p= 0.005 ). Recurrence of AF was also associated with high level of NT proBNP > 220 pg/ml ( 34.8 % vs. 65.2% p=0.008), LA volume index >26cc/m2 ( 19.0 % vs. 81.0 %, p=0.008), hypertension ( 85.2 % vs. 14.8 %, p=0.03), and paroxysmal AF ( 37.0 % vs. 63.0 %, <0.001). By multivariate Cox regression analysis, NT proBNP > 220 pg/ml (hazard ratio=2.75, 95% CI 1.09 to 6.93, p = 0.032) and paroxysmal AF (hazard ratio=2.59, 95% CI 1.08 to 6.21, p = 0.033) were significant independent predictors in recurrence of AF. Conclusions: This study suggests that elevated NT-proBNP level before catheter ablation is associated with recurrence of AF and predict 3 months outcome after procedure.