This study examined 12-month outcome following polytrauma and mild Traumatic Brain Injury (MTBI) in injured service members who were evaluated at the Walter Reed Army Medical Center following injuries sustained in combat theater during Operations Iraqi Freedom or Enduring Freedom (OIF/OEF). Patients (N=48) completed the Neurobehavioral Symptom Inventory within 2 months of injury (M=15.9 days, SD=13.6) and a telephone interview at 12 months post injury (M=13.1, SD=0.8). More than half of the sample met DSM-IV criteria for Postconcussional Disorder within 2 months (54.2%) and 12 months post injury (55.6%). Over time, 20.8% showed an improvement of symptoms, 16.7% worsened, and 33.3% had persistent symptoms. At 12 months, most were on active duty (79.2%), reported that they were satisfied with life (81.3%), and indicated that their health status was either “excellent,” “very good,” or “good” (66.7%). However, a substantial percentage reported that they continued to take medications (81.3%), experienced bodily pain (72.9%), needed help with daily activities (29.2%), and were currently in treatment with a mental health professional (39.6%). A small percentage reported that they had recently had suicidal or homicidal thoughts (10.4%). Extended follow-up is recommended for service members who sustain an MTBI in the context of polytrauma.