Given the association of injury and posttraumatic stress disorder (PTSD), we examined whether head injury might be associated with increased frequency and severity of PTSD. Using a mail survey, we queried 143 male combat veterans with and without PTSD, who had previously participated in PTSD research in our laboratory, about their history of head injury. Respondents with a PTSD diagnosis were significantly more likely to report a history of head injury than those without. Patients with a history of head injury also reported more severe symptoms of PTSD compared with PTSD patients without head injury. The association of head injury and PTSD was not due to greater combat exposure in the head-injured group. Head injury is associated with a greater likelihood of developing combat-related PTSD and with more severe PTSD symptoms. This retrospective study did not address mechanisms that could account for this finding. The results indicate head injury should be systematically assessed by both nonpsychiatric and psychiatric physicians concerned with the psychological sequelae of exposure to victimizing experiences.