Background: It has been proposed that posttraumatic stress disorder (PTSD) patients who experience significant dissociation upon exposure to traumatic reminders may do less well in trauma-focused therapies. We explored whether a sequenced two-component treatment in which an emotion regulation skills training module preceding exposure would improve outcomes for those with significant dissociation., Methods: Analyses were conducted on data from an RCT in which 104 women with PTSD related to childhood abuse were assigned to one of three treatment conditions: Skills Training in Affective and Interpersonal Regulation (STAIR) followed by Narrative Story Telling (NST; STAIR/NST), STAIR followed by supportive counseling (SC; STAIR/SC), or SC followed by NST (SC/NST)., Results: Baseline dissociation was associated with differential outcome such that at low levels of dissociation the three treatments were equally effective but at higher levels STAIR/NST resulted in greater reductions in dissociative symptoms. Level of baseline dissociation did not moderate the effect of the treatments on PTSD outcome. At all levels of baseline dissociation, STAIR/NST produced better PTSD outcome. At posttreatment, however, participants with high dissociation treated with STAIR/NST continued to improve during follow-up, those treated with STAIR/SC maintained gains, and those treated with SC/NST experienced loss of posttreatment PTSD symptom gains., Conclusions: The differential results observed among the treatments depending on severity of dissociation at baseline and at posttreatment suggest the potential clinical utility of identifying a dissociative subtype of PTSD and of the benefits of sequenced, phase-oriented treatment approaches., (© 2012 Wiley Periodicals, Inc.)