Résumé : Objectives: Post-traumatic stress disorder (PTSD) is a major public health problem defined by three symptom clusters: intrusion thoughts, avoidance mechanisms and hyper-arousal. Several authors have emphasized, that some or all of these symptoms related to a past traumatic experience could be reactivated, even after long asymptomatic periods. This study investigates the role of an additional trauma in the reactivation of a childhood trauma among a group of former hidden children (n = 65), the Jewish youths who spent World War II in various hideaway shelters in Nazi-occupied Europe. They were compared with a control group.Method: The presence or absence of an additional trauma in adulthood was assessed and PTSD symptoms were measured by using the Impact of Event Scale-Revised.Results: An additional trauma reactivates PTSD symptoms of intrusion thoughts and, marginally, symptoms of hyper-arousal. At the opposite, symptoms of avoidance were not reactivated.Conclusion: Our results confirm the role of an additional trauma in the reactivation of traumatic memories, related to an earlier trauma, in later life. Clinical and theoretical implications are discussed and perspectives are proposed.