Introduction: Endothelial function has been shown to be deteriorated by the presence of atrial fibrillation (AF). Therefore, we hypothesized that serial change in the endothelial function can predict the recurrence of AF after catheter ablation (CA). Objectives: The purpose of this study was to examine the predictive value of endothelial function as a marker for recurrence of AF after CA. Methods: The consecutive 156 AF patients who underwent CA for AF were included in this study. All patients assessed their endothelial function by the reactive hyperemia-peripheral arterial tonometry (RH-PAT) and the RH-PAT index (RHI) was measured before CA, and 3 and 6 months after CA. To investigate the factors correlated with AF recurrence, clinical variables and RHI before CA, 3 and 6 months after CA were examined in patients with and without recurrence of AF. The recurrence of AF was defined as the occurrence of AF at the time of 6 months after CA. Results: AF recurrence was not observed in 125 patients (80%), but was observed in the remaining 31 patients (20%). Disease duration of AF (p=0.028), RHI before CA (p<0.001), RHI 3 month after CA (p=0.037), the difference in RHI before and 3 month after CA (p<0.001) were significantly correlated with AF recurrence. The multivariate Cox hazard analysis revealed that the difference in RHI before and 3 month after CA independently correlated with the recurrence of AF (p<0.001, Hazard ratio: 0.168). Furthermore, the value of RHI 3 month after CA, which decreased 0.015 or more compared with that before CA, was the independent predictor of AF recurrence (sensitivity: 0.613, specificity: 0.880, area under curve 0.722). Kaplan-Meier analysis demonstrated a significantly higher probability of AF recurrence when the RHI value 3 months after CA showed a decrease over 0.015 (log-rank test: p<0.001). Conclusions: The change in the endothelial function following CA sensitively reflects the recurrence of AF. The decrease in the RHI 3 months after CA compared to that before CA, with a cu-off value of 0.015, was an independent significant predictor of AF recurrence. Therefore, no recurrence of AF can be expected by the absence of decrease in RHI. We might be able to stop anti-arrhythmic drugs and anticoagulants according to the RHI improvement 3 month after CA.