Introduction Esophageal injury is a rare but the most fearful complication in catheter ablation of atrial fibrillation (AF). The aim of this study was to investigate the anatomic relationship between the left atrium (LA), the pulmonary veins (PV), and the esophagus and provide clinical information to avoid the risk of atrioesophageal fistula during AF ablation. Methods Multidetector spiral computed tomography (MDCT) of 107 patients (73.8% men, mean age 58짹 11 years) with drug refractory AF and 58 control subjects (48.3% men, mean age 52 짹 13 years) were analyzed. We measured variables as follows; 1) the distance between the ostia of the PVs and ipsilateral esophageal border, 2) The presence and the thickness of pericardial fatpad around each PV, 3) The contact witdth/length and the presence of fatpad between the LA and the esophagus. Results The mean LA size was larger in the patient group than in the control group. The distance between the esophagus and the ostia of the right superior PV (RSPV), the right inferior PV (RIPV), the left superior PV (LSPV), and the left inferior PV (LIPV) was 27.2 짹 9.3 mm, 23.8 짹 9.6 mm, 2.3 짹 9.0 mm, and 6.1 짹 8.5mm, respectively. There was no significant difference in PV-esophagus distance between the patient and the control group. The pericardial fat pad around superior PV was present in more than 90%. However, RIPV and LIPV were covered with fat pad in 20.6% and 52.9%, respectively. There was significant difference between the patient group (45.8%) and the control group (79.3%) in the fat pad around LIPV (p=0.002). The average width of LA-esophagus contact in the patient and the control group was 13.8 짹 5.1 mm and 11.5 짹 5.5 mm, respectively (p=0.037). the average length of LA-esophagus contact in the patient and the control group was 22.9 짹 11.7 and 14.6 짹 8.0, respectively (p<0.001). There was no contact between the esophagus and the LA due to significant amount of fat pad in 8.1%. Conclusion The esophagus is located closer to the left-side PV than to the right-side PV. Caution should be exercised when ablating LIPV because the esophagus is located in close proximity to LIPV and half of the LIPV in patients with AF are not covered with fat pad. The contact area between the esophagus and the LA was much larger in patients with AF than in those without AF.