BackgroundChylothorax resulting from chest tube injury to the thoracic duct is very rare and underreported.ObjectiveThe purpose of this case report is to exemplify this rare but potentially significant complication of chest tube thoracostomy.Case reportAn 86-year-old woman presented with sepsis and a massive right pleural effusion; she developed a chylous effusion with the pleural fluid triglyceride level of 158 mg/dL 2 days after a traumatic chest tube insertion. All investigations excluded common causes of non-traumatic chylothorax. The chylothorax improved after fasting and implementation of a medium-chain triglyceride diet.ConclusionThe optimal depth of insertion of the chest tube typically ranges from 5 to 15 cm, ensuring all sideports are within the chest and the proximal port is at least 2 cm beyond the rib margin. Traumatic chylothorax secondary to chest tube insertion should be included in the differential diagnosis of patients presenting with chylothorax after a thoracostomy tube