Introduction: Hypertension is known as a risk factor to progress the etiology of atrial fibrillation (AF). However, influence of non-dipper on AF recurrence after pulmonary vein isolation (PVI) remains unknown. Methods: We investigated the clinical impact of non-dipper evaluated by 24-hour ambulatory BP monitoring on the long-term outcome for AF recurrence in 76 AF patients underwent the PVI. Results: All of 76 patients (mean age:66±9 years, hypertension:78%, non-paroxysmal AF:24%) had procedural success of PVI. Twenty patients had AF recurrence during follow-up of median of 1158 days post-PVI. There was no difference in BP level between the AF recurrence and non-recurrence groups (average 24h-systolic BP:126±17 vs. 125±14mmHg, P=0.84). On the other hand, the patients with non-dipper had a higher AF recurrence than those with dipper (38.9% vs. 15.0%, P=0.018). In Cox hazard analysis adjusted by age, non-paroxysmal AF, and average 24h-systolic BP level, the non-dipper was an independent predictor of AF recurrence (HR 2.78 [95%CI: 1.05-7.34], P=0.039). The patients with non-dipper had a larger left atrial (LA) volume index than those with dipper (45.9±17.3 vs. 38.3±10.2ml, P=0.037). In 58 patients underwent the high-density voltage mapping in LA, 11 patients had low voltage area (LVA) defined as an area with a bipolar voltage < 0.5mV. There was no difference in existence of LVA between patients with non-dipper and those with dipper (22.2% vs. 16.1%, P=0.555). Conclusions: Non-dipper is an independent predictor of AF recurrence after PVI. Management for abnormal diurnal BP variation may be important in patients after PVI.