Background: A pulmonary hypertension, hypoxemia, and acidosis in patients with chronic lung disease (CLD) were known to cause atrial arrhythmias including atrial fibrillation (AF). The outcome of radiofrequency catheter ablation (RFCA) of AF in the patients with CLD has not been reported. Purpose: We investigated the efficacy of RFCA for AF associated with CLD and relationship of anatomic alteration of pulmonary veins (PVs) and left atrium (LA) in CLD patients with arrhythmogenecity of AF. Methods: 15 patients who had significant CLD and underwent RFCA of AF were analyzed. The CLD included COPD, tuberculosis destructed lung (TDL), or interstitial lung disease (ILD). And the sex-age, procedure era (짹1 year) matched 60 patients (1:4) that receiving AF ablation without CLD were selected as control group. 3-demensional computed tomography of the LA and PVs and 2-demensional echocardiography were taken in all subjects prior to RFCA. The RFCA of AF was PV isolation without (paroxysmal AF) or with (persistent AF) linear ablations at multiple sites and elimination of non-PV foci if identified. Results: Mean age of the CLD patients was 60짹12 years and all 15 patients were male. Eight patients had COPD, TDL in 6, and ILD in 1. 10 of 15 were paroxysmal AF. PV morphology was significantly altered and deformed according to lung lesions (obliteration of corresponding PVs or bulging of PV antrum, etc). Non-PV foci were observed in 4/15 (26.7%) in CLD group, which were more common than control (3/60, 5.0%, p=0.026). All non-PV foci were from the right atrium (RA) and included coronary sinus, superior vena cava, low crista terminalis, and high crista terminalis to RA septum in 4 patients, respectively. The AF recurrence rate (26.7%) in CLD group was not different from control group (18.3%, NS). Conclusions: Non-PV foci from the RA were more frequently observed in CLD group than in control. The ablation of AF in CLD patient was safe and effective as in the patients with normal lung.