Traumatic brain injury (TBI) is a common condition, especially among military members. Twelve to 23 percent of service members returning from Operations Enduring Freedom, Iraqi Freedom, and New Dawn (OEF/OIF/OND) experienced a TBI while deployed. Although various criteria are used to define TBI severity, the majority of documented TBI events among OEF/OIF/ OND service members may be classified as mild in severity, or mTBI, according to the definition used by the Veterans Health Administration and Department of Defense (VA/DoD). While some researchers suggest most individuals recover within three months of an mTBI, others estimate that 10 to 20 percent of individuals continue to experience post-concussive symptoms (e.g., headaches, dizziness, balance problems) beyond this time fame. This estimate may be higher among OEF/OIF service members given the frequency of multiple TBI events, concomitant mental health conditions such as depression and posttraumatic stress disorder (PTSD), and other factors unique to combat deployments. As such, deployment-related mTBI is a significant issue for the VA, as patients who report ongoing mTBI symptoms may require the attention from a range of health care professionals. This evidence synthesis review will be used by the VHA TBI Advisory Committee to develop strategies to identify those at-risk for long-term mTBI effects, inform clinical practice, determine resource allocation, and identify future research priorities. The key questions were: Key Question #1. For Veteran/military populations, what is the prevalence of health problems (such as pain, seizure disorders, headaches, migraines, and vertigo), cognitive deficits, functional limitations (such as employment status, changes in marital status/family dynamics), and mental health symptoms (such as PTSD and depression) that develop or persist following mTBI? Key Question #2. What factors affect outcomes for Veteran/military patients with mTBI? Key Question 2A: For Veteran/military populations, are there pre-injury (premorbid) risk/protective factors (e.g., pre-injury mental health factors, genetic factors, or prior concussions) that affect outcomes for mTBI? Key Question 2B: For Veteran/military populations, are there post-injury risk/protective factors (e.g., PTSD) that affect outcomes for mTBI? Key Question #3. What is the resource utilization over time for Veteran/military patients with mTBI?