Repair of traumatic abdominal wall hernia (TAWH) has been reported to be necessary. Reported here is one case of TAWH without repair. A 27-year-old man was accidentally sandwiched between a rock and a truck and admitted to our emergency department. There was a swelling of 10 cm in the right upper quadrant of the abdomen. The enhanced computed tomographic scan demonstrated a large abdominal wall muscular defect, transverse colon protrusion, and the presence of subcutaneous emphysema at the site. Based on these findings, lacerated transverse colon entrapped in TAWH was diagnosed. The patient underwent emergency laparotomy for laceration of the transverse colon, duodenum and pancreas, and open book fracture of the pelvis. Repair of the hernia was not performed because of the possibility of abscess formation by stool contamination. However, the hernia disappeared and the patient is doing well without recurrence of hernia 16 months after injury.