Diaphragmatic rupture is a serious complication of thoracoabdominal trauma. The condition may be missed initially. We describe the clinical course of a patient who sustained blunt abdominal trauma in a car accident. His diaphragmatic injury passed unnoticed, to present two years later with left tension viscerothorax, a rarely reported and hardly recognised entity. Nasogastric tube insertion aborted the emergency situation and the hernia was repaired successfully in a semielective setting.