Traumatic memories, and the mechanisms by which they operate, continue to occupy a central role in the scientific investigation of risk factors for the development of posttraumatic stress disorder (PTSD). However, empirically based studies are constrained by practical and ethical considerations and are limited to naturalistic models. Consequently, the paradigms most appropriate for the exploration of the relationship between traumatic memories and PTSD have been identified in conditions involving traumatic events where memories may be compromised. Indeed, traumatic brain injury, a condition that is commonly associated with memory impairment, has often been utilized as a naturally occurring model for the study of traumatic memory and its contribution to the development of PTSD. This article presents a critical review of these research efforts and discusses their theoretical and clinical implications.