Trauma survivors, and particularly torture survivors, suffer from high rates of chronic pain and posttraumatic stress disorder (PTSD) for years afterward, along with alterations in the function of the pain system. On the basis of longitudinal data on PTSD symptomatology, we tested whether exposure to torture, PTSD or PTSD trajectories accounted for chronic pain and altered pain perception. Participants were 59 torture survivors and 44 age-matched healthy control subjects. Chronic pain was characterized. Pain threshold, pain tolerance, conditioned pain modulation (CPM), and temporal summation of pain were measured. Three PTSD trajectories were identified among torture survivors; chronic, delayed, and resilient. Lack of CPM and more intense chronic pain was found among the chronic and delayed groups compared with the resilient and healthy control groups. Temporal summation of pain was strongest among the chronic group. PTSD trajectories mediated the relationship between torture and CPM. It appears that the duration and severity of posttraumatic distress, rather than the exposure to trauma, are crucial factors that mediate the association between trauma and chronic pain. Because PTSD and its resultant distress are measurable, their evaluation seems particularly important in the management of pain among trauma survivors. The results may be generalized to other instances in which chronic pain persists after traumatic events. Perspective: This article presents the mediation effect of PTSD trajectory on pain modulation among trauma survivors suggesting that it is the duration and severity of PTSD/distress, rather than the exposure to trauma per se, that influence the perception and modulation of pain. (C) 2016 by the American Pain Society