We describe the case of a 35-year-old man who had suffered a severe multitrauma with blunt thoracic injury, left scapula and humerus fractures 5 years earlier. At the time of the trauma, a diaphragmatic lesion went unnoticed. Five years later, the patient had a 24-h history of increasingly severe abdominal pain with repeated vomiting. Helical CT showed a portion of the left hemidiaphragm avulsed from its insertions on the ribs with large-bowel loop obstruction herniated in the left hemithorax. The preoperative CT diagnosis was confirmed by surgery: reduction of the hernia and reinsertion of the hemidiaphragm to the lumbocostal arch were performed.