Chylothorax is an uncommon but well recognized complication of esophagectomy. We present a case 65-year-old man with midthoracic esophageal carcinoma who Underwent three stage radical esophagectomy by right thoracotomy. The postoperative course was uneventful until the 12th postoperative day, when the right chest tube was removed. On the 19th postoperative day the pa t complained of dyspnea, and chest roentgenogram showed massive pleural effusion in the right lower chest. A chest tube was reinserted into the right lower pleural cavity. The pleural fluid showed milky appearance end its amount was about 800 ml/day. The characteristics and composition of the pleural fluid was similar to those of chyle. Though conservative management was applied for 20 days, pleural effusion was remained. and then explo-laparotomy for thoracic duct ligation was performed near right crus, but chyle leakage persisted. We treated by intrapleural infusion of OK-432 (picibani1), without major side effects. This procedure should be considered one of the treatment of option for patient with persistent chylothorax not responding to conservative and surgical management. (J Korean Surg Soc 2001;61:105-109)