Some variations in pulmonary vein anatomy can have serious consequences in patients undergoing lung surgery, but clinicians rarely encounter patients with these variations. We report here a thoracoscopic lobectomy for right lung cancer in a patient with three right vein ostia. Preoperative review of three-dimensional 64-row multidetector computed tomography (3D-MDCT) of the patient showed a variation that was not confirmed in transverse plane computed tomography films. However, the variant anomaly was confirmed during thoracoscopic right lower lobectomy. The postoperative course was uneventful, and the patient was discharged on postoperative day 10. Preoperative 3D-MDCT of the pulmonary vein produced a precise preoperative simulation for the surgeon and clearly showed the orientation of the patient's vascular variant during surgery. This imaging technology contributes to safer thoracic surgery, especially thoracoscopic surgery.