BACKGROUND Postoperative chylothorax remains an important cause of reoperation and prolonged hospital stay after esophagectomy for the treatment of esophageal carcinoma. Chylothorax is potentially life threatening and difficult to manage. The benefit of routine thoracic duct ligation is controversial. A promising alternative is to identify chyle leaks at the time of esophagectomy and perform the ligation selectively. We developed a novel technique to identify chyle leak at the time of esophagectomy and compared it with routine ligation of thoracic duct. METHODS This cohort study involved all of the qualified patients with resectable esophageal carcinoma treated between March 1, 2011, and December 31, 2015, by a single surgical team at West China Hospital. Patients receiving routine en masse ligation of the thoracic duct were assigned to group A, and patients receiving selective en masse ligation of the thoracic duct were assigned to group B. All patients in the selective ligation group received 120 mL olive oil orally before the operation. The end point included frequencies of chyle leak detected at the time of esophagectomy, postoperative chylothorax, and need for chylothorax-related reoperation. RESULTS The study enrolled 296 patients who fulfilled the study requirement: 55 in group A and 241 in group B. Patients in group A experienced significantly higher incidences of postoperative chylothorax and chylothorax-related reoperation than group B (9.1% vs 0% [p < 0.01] and 3.6% vs 0% [p < 0.01]). Incidence of detection of intraoperative chyle leak (chylothorax plus chylous ascites) was significantly higher in group B than in group A (9.5% vs 0%, p < 0.01). No intraoperative or postoperative complications related to preoperative oral olive oil administration or selective en masse ligation of the thoracic duct were observed. CONCLUSIONS Our method of selective en masse ligation of the thoracic duct during esophagectomy was feasible and safe and was associated with reduced rates of postoperative chylothorax.