Abstract: Objective: This study aimed to examine associations between deployment to US military bases with open burn pits and mental health conditions and injury-related mortality among veterans. Methods: We analyzed a cohort of 439,919 US Army and Air Force Veterans deployed to Operation Enduring Freedom or Operation Iraqi Freedom (2001–2011). Deployment records were linked with Veterans Health Administration data. Exposure was defined as cumulative days deployed to bases with burn pits. Results: Deployment duration to burn pit–exposed bases are associated with increased risk of postdeployment diagnoses of posttraumatic stress disorder, intracranial damage and injuries, and unintentional injury-related mortality. Conclusions: Cumulative exposure to open burn pits was associated with elevated risk of long-term psychiatric and injury-related outcomes among veterans. These findings highlight the need for continued monitoring and support for service members exposed to environmental hazards during military deployment.