A significant number of Operation Iraqi Freedom/Operation Enduring Freedom (OEF/OIF) veterans are returning from deployment and presenting to Veterans Health Administration (VHA) polytrauma clinics with elevated rates of posttraumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI). Inherent to the accurate assessment and treatment of this diagnostically complex group of veterans is the assumption that the construct of PTSD is the same in this population as in other trauma groups. To our knowledge, no previous study has examined the structure of PTSD in this relevant and fast-growing population of treatment-seeking OEF/OIF veterans. Evidence suggests that the latent structure of PTSD symptoms is best represented by a four-factor model, rather than the three-factor model found in the current DSM–IV–TR. Thus, we examined the three and four-factor models using the PTSD Check List-Civilian (PCL-C) in a sample of treatment-seeking OEF/OIF veterans seen through a VHA polytrauma clinic. A chart review was conducted for OEF/OIF veterans (N= 361) seen through a VHA outpatient polytrauma clinic from September 2007 through August 2008. Participants completed the PCL-C as part of a comprehensive polytrauma evaluation. Confirmatory factor analyses showed that the DSM–IV–TR three-factor model did not fit the data well. A direct comparison showed that the four-factor model provided a superior fit relative to the three-factor model. Results extend the generalizability of the four-factor model to OEF/OIF veterans presenting to Veterans Health Administration (VHA) polytrauma clinics.