Background: Flail chest (FC) is known to account for high mortality and morbidity and is typically treated with conservative care. Operative fixation of FC has been advocated as an alternative treatment choice. This prospective randomized controlled trial aims to compare surgical and nonsurgical management of FC in patients with severe polytrauma. Methods: Severe polytrauma patients with FC admitted between January 2015 and July 2017 to our trauma center were investigated. The enrolled patients were randomly assigned to the surgical or nonsurgical group. Basic characteristics of injury and clinical outcomes were compared. Results: Fifty patients entered final analysis, with 25 patients in each group. Operative rib fixation was associated with shorter duration of mechanical ventilation (7 d [interquartile range {IQR} 6-10] versus 9 d [IQR 7-12], P = 0.012), shorter ICU stay (10 d [IQR 7-12] versus 12 d [IQR 9-15], P = 0.032), lower risk of adult respiratory distress syndrome (28% versus 60%, P = 0.045), pneumonia (48% versus 80%, P = 0.038), and thoracic deformity (8% versus 36%, P = 0.037) and less pain while coughing (pain score 6 [IQR 3-8] versus 8 [IQR 4-9], P = 0.029) and deep breathing (pain score 5 [IQR 3-9] versus 7 [IQR 3-9], P = 0.038). Subgroup analysis was conducted by presence of pulmonary contusion. Shorter time on the ventilator use and ICU stay associated with rib surgery was not observed in patients with pulmonary contusion. Conclusions: This study reveals that surgical rib fixation may provide some critical care benefits for severe polytrauma patients with FC, including less medical resource use and lower risk of complications. Further studies should be designed to optimally identify patients who are most likely to benefit from this surgery. (C) 2019 Elsevier Inc. All rights reserved.