The relationship between posttraumatic amnesia (PTA) and symptoms of posttraumatic stress disorder (PTSD) was examined in 282 outpatients at a mean of 53 days after traumatic brain injury (TBI). Patients were assessed for TBI severity, intrusive and avoidant PTSD-type symptoms, and psychological distress, and were stratified into four comparison groups by duration of PTA. Levels of PTSD-type symptoms and psychological distress did not differ significantly between groups. Even patients with PTA >1 week reported intrusive and avoidant PTSD-type symptoms. However, when patients were stratified into those with PTA of <1 hour or >1 hour, the former were more likely to report such symptoms. TBI patients with brief PTA are more likely to experience PTSD-type reactions, but severe TBI with prolonged PTA is not incompatible with such reactions in a subset of patients. Possible mechanisms that could account for this finding are discussed.