Purpose: A flail chest is one of most challenging problems for trauma surgeons. It is usually accompanied by significant underlying pulmonary parenchymal injuries and mayled to a life-threatening thoracic injury. In this study, we evaluated the treatment result for a flail chest to determine the effect of trauma localization on morbidity and mortality. Methods: Between 2004 and 2011, 46 patients(29 males/17 females) were treated for a flail chest. The patients were divided into two group based on the location of the trauma in the chest wall; Group I contained patients with an anterior flail chest due to a bilateral costochondral separation (n=27) and Group II contained patients with a single-side posterolateral flail chest due to a segmental rib fracture (n=19). The location of the trauma in the chest wall, other injuries, mechanical ventilation support, prognosis and ISS (injury severity score) were retrospectively examined in the two groups. Results: Mechanical ventilation support was given in 38 patients(82.6%), and 7 of these 38 patients required a subsequent tracheostomy. The mean ISS for all 46 patients was $19.08{pm}10.57$. Between the two groups, there was a significant difference in mean ventilator time (p<0.048), but no significant difference in either trauma-related morbidity (p=0.369) or mortality (p=0.189). Conclusion: An anterior flail chest frequently affects the two underlying lung parenchyma and can cause a bilateral lung contusion, a hemopneumothorax and lung hemorrhage. Thus, it needs longer ventilator care than a lateral flail chest does and is more frequently associated with pulmonary complications with poor outcome than a lateral flail chest is. In a severe trauma patient with a flail chest, especially an anterior flail chest, we must pay more attention to the pulmonary care strategy and the bronchial toilet.