Adult research suggests that the dissociation criterion of acute stress disorder has limited validity in predicting posttraumatic stress disorder (PTSD). We addressed this issue in child and adolescent survivors (n=367) of road accidents. Dissociation accounted for no significant unique variance in later PTSD, over and above other acute stress disorder criteria. Furthermore, thresholds of either three or more re-experiencing symptoms, or six or more re-experiencing/hyperarousal symptoms, were as effective at predicting PTSD as the full acute stress disorder diagnosis.