The present prospective study evaluates the predictive value of 2 different types of dissociation (psychological and somatoform peritraumatic dissociation), and dysfunctional cognitions on symptoms of posttraumatic stress disorder (PTSD) at 6 months. Assessment of dissociation, PTSD symptoms, and dysfunctional cognitions took place in 49 participants approximately 3 weeks after a traumatic event. Six months later PTSD symptoms were assessed again. The effect of both psychological and somatoform peritraumatic dissociation disappeared after controlling for initial PTSD numbing symptoms. Dysfunctional cognitions predicted PTSD at 6 months after controlling for initial numbing symptoms. The present study indicates that peritraumatic dissociation may not be a predictor of PTSD. In contrast, maladaptive posttraumatic coping behavior like persistent dissociation and dysfunctional cognitions may be predictors.