This report describes the reactivation of a posttraumatic stress disorder (PTSD) after a minor head injury in two young women who had recovered from extreme stress caused by sexual abuse during adolescence. Intrusive thoughts, images, dreams, and phobic avoidance bear a direct relationship to the specific circumstances of both head injury and sexual abuse, and were associated with obsessive-compulsive symptoms, generalized anxiety with panic, and depression. These findings suggest that in some individuals minor head injuries may induce not only extreme stress reactions, but also cause the reactivation of symptoms related to previous traumatic experiences.