A 39-year-old man was admitted with a stab wound to left lower neck. Chest X-ray revealed a left hydropneumothorax. Thoracentesis was performed and analysis of the fluid revealed chyle. Patient was treated conservatively by closed chest drainage and total parenteral nutrition. On the basis of this clinical report and review of the literature, it is concluded that thoracic duct injury should be kept in mind in penetrating neck trauma and conservative treatment should be the first line therapy.