Unstable chest wall injuries, including flail chest, have traditionally been treated non-operatively. Operative treatment has become more common in recent years, but it remains unclear which, if any patients, benefit from surgery. The authors randomized 207 patients with unstable chest wall injuries to operative versus non-operative treatment. The primary outcome was ventilator free days (VFDs), and the secondary outcomes were total ventilator days, length of stay (LOS) in the intensive care unit (ICU) and hospital, and complications. The overall mortality rate was significantly lower in the operative group (0% vs. 6%, p = 0.011). Overall, there was no significant difference between the two groups on any other outcomes. When patients who were intubated at randomization were analyzed separately, those who underwent surgery had significantly more ventilator-free days and significantly shorter hospital LOS. There were no differences in the non-intubated cohort. Overall, this trial suggests surgical stabilization of unstable chest wall injuries may have benefit, but only in patients who are intubated.