The purpose of the present study was to gather prospective longitudinal data on the long-term course and outcome of chronic posttraumatic stress disorder (PTSD). The target population for this study was 74 injured traffic accident victims who had been previously followed-up for one year after the trauma. Nineteen of the original 24 PTSD subjects (79%) and 39 of the original 50 Non-PTSD subjects (78%) were available for this study, which took place during the fourth year after the accident. Our results show that 10 (53%) of the 19 patients with PTSD at one-year still suffered from PTSD after another two-year follow-up interval, while 9 recovered from PTSD during this follow-up period. Only 2 of the 39 without PTSD at one year developed delayed onset PTSD. The best predictor of recovery from chronic PTSD was the initial level of posttraumatic reaction immediately after the accident. These results demonstrate that spontaneous recovery from PTSD can occur even among patients who are currently considered chronic. Severity of initial reaction to the trauma appears to be a major risk factor for non-remitting chronic PTSD.