United States (U.S.) Veterans Affairs (VA) and Department of Defense (DoD) healthcare facilities are increasingly serving a large population of Operation Enduring Freedom and Operation Iraqi Freedom (OEF/OIF) veterans who have sustained traumatic brain injury (TBI), suffer from post-traumatic stress disorder (PTSD), or have both a history of TBI and current PTSD (TBI/PTSD). Mild TBI (mTBI) is considered the most common form of TBI. Uncertainty exists regarding the long-term health outcomes of mTBI as well as the validity of criteria used to assess for a history of this injury. Symptoms that may be attributable to mTBI are similar to symptoms of PTSD. It is unknown whether findings from civilian populations with both a history of mTBI and PTSD (mTBI/PTSD) are applicable to individuals with combat-related mTBI/PTSD. Current evidence-based practices to screen, diagnose, prospectively evaluate, and treat mTBI symptoms or PTSD may be less accurate or effective if and when these conditions co-occur. Thus, there is a need to develop an evidence base to identify best practices to define, diagnose, evaluate, and manage patients with mTBI/PTSD, particularly in U.S. veterans of OEF/OIF.