Traumatic lung herniation is an unusual clinical problem. This case report describes a morbidly obese individual who sustained significant chest trauma in a motor vehicle accident. Lung herniation was noted at the time of delayed respiratory failure necessitating ventilation. The significance of the lung hernia in this patient's respiratory failure is uncertain. The lung hernia was repaired surgically to relieve pain, prevent incarceration, and optimize respiratory function. After a brief period of postoperative ventilation, the patient recovered markedly and has been well since.