Peritraumatic dissociation has consistently been found to be strongly correlated with PTSD. Yet it was unclear how peritraumatic dissociation affected the physiological responses of individuals with or without PTSD. Eighty-six women with a history of attempted or completed sexual assault were recruited to participate. Script-driven imagery procedures were used to assess changes in heart rate and skin conductance responses of the women during a neutral, positive, fearful, and trauma-related script. The pattern of physiological responses suggested that peritraumatic dissociation was associated with elevated physiological responses. Peritraumatic dissociation also seemed to accentuate physiological responses to general threat cues in sexual assault survivors without PTSD as well as to trauma-specific cues in survivors with PTSD. The pattern of responses during each script was also specific to the participants’ self-reported peritraumatic dissociation and level of PTSD symptoms. These findings suggested that it would behoove clinicians working with survivors of trauma to assess for peritraumatic dissociation even if PTSD is not present, as it may inform decisions about the length of exposure treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)