Jejunal perforation is extremely rare in trauma especially without initial involvement of the abdomen. We present the case of a delayed jejunal perforation after thoracic trauma with no initial indication of abdominal trauma in a 55-year-old man who was admitted to our department after a road traffic accident. The patient sustained thoracic trauma with rib fractures of the left hemithorax and hemopneumothorax and a mild head injury. On the fourth day of his in-hospital stay, he complained of severe abdominal pain and signs of acute abdomen were observed. He underwent emergency laparotomy where a perforation of the jejunum near the ligament of Treitz was noticed and sutured. His postoperative recovery was uneventful. Physicians treating trauma should always have a high degree of suspicion regarding rare abdominal injuries, with delayed presentation, even if no abdominal involvement is noticed during the initial survey.