Between January 1983 and May 1987, 255 esophagectomies were performed for carcinoma of the middle (40 patients) or lower (215 patients) esophagus. All patients were operated upon through a left thoracolaparotomy and underwent a radical en bloc resection of the tumor along with all palpable mediastinal nodes. Ten patients had chylothorax develop postoperatively. There were seven men and three women with a mean age of 65.7 years (range of 37.0 to 81.0 years). Parameters that were statistically evaluated for possible correlation to increased incidence of chylous fistula were age, sex, site and size of tumor, histologic type, mediastinal lymphatic involvement and elective prophylactic ligation of the major thoracic duct (MTD) at the conclusion of the procedure. It was found that elective ligation of the MTD was associated with a lower occurrence of chylothorax (2.1 per cent) as compared with those with no routine ligation (9 per cent), p less than 0.05. The leak was successfully treated by repeated thoracotomy and mass ligation of the MTD in eight patients, while one patient underwent closed tube thoracostomy. In one instance, only a pleuroperitoneal shunt was performed. The over-all hospital mortality rate from chylothorax was 10 per cent and there was a late death because of pneumonia. We recommend prophylactic ligation of the MTD in all instances of extensive esophageal resection for the prevention of chylothorax, as well as early thoracotomy for the management of established leaks.