Introduction: Nearly 10% of all combat injuries during the most recent conflicts in Iraq and Afghanistan involve thoracic trauma. The long-term outcomes of these combat-related injuries with respect to lung function have not been fully evaluated. Limited research in civilian polytrauma patients have shown significant obstructive physiology in nearly half of their population without clear etiology. We sought to further characterize the extent to which these active duty service members (ADSM) are chronically affected by their thoracic injuries. Materials and Methods: We conducted a retrospective chart review and analysis of ADSM who sustained thoracic injuries while deployed in support combat operations from 2003 to 2013. Using the Department of Defense Trauma Registry, 2,049 patients were found to have sustained thoracic trauma during these conflicts, of which we were able to identify 298 patients with postinjury pulmonary function testing (PFT) available for analysis. Following standardization of these tests using the established reference values, PFT was compared to a representative population of ADSM. Additional analysis was completed to detect incidence of abnormal PFTs when compared to both type of injury (burn, blunt, penetrating, and other) and also Injury Severity Score. Results: In our patient population, there was a significant increase in abnormal PFTs when compared to a representative population. Of these, 31.8% of patients displayed obstructive physiology versus 3.7% in the control (P < 0.001), 24.5% displayed restrictive or restrictive pattern (those without full lung volumes available utilizing forced vital capacity) versus 4.9% (P < 0.0001), and 7.9% displaying mixed pattern. Further, increasing rates of abnormal PFTs were identified in comparison to Injury Severity Score (odds ratio 1.03). There was no significant increase in abnormal PFTs when stratified by type of injury. Finally, there was no significant change identified in pulmonary function before and after injury in our limited population of 19 patients. Conclusions: There is a significant increase in the percent of abnormal PFTs in ADSM following thoracic injury when compared to patients with similar risk factors and baseline health. It is unclear why the rates of obstruction are high in our population as previous research has not definitively shown increased rates of asthma in previously deployed, uninjured ADSM; however, this finding is consistent with limited previous research in civilian trauma patients. Further research into the long-term outcomes of thoracic trauma and occupational exposures of combat is paramount for improved outcomes going forward.