Thoracic duct injury resulting in chylothorax is a well-known and documented complication of thoracic surgery. However, chylothorax under tension is a rarely reported complication that results in respiratory and hemodynamic collapse. Early recognition and treatment of this entity are essential for optimal patient outcome. Herein we present two cases of postoperative tension chylothorax followed by a review of the diagnostic work-up and therapy for this complication.