Despite the high rate of trauma and PTSD among individuals with borderline personality disorder (BPD), no studies have specifically evaluated the treatment of PTSD in a BPD population. These case studies illustrate the use of a protocol based on prolonged exposure therapy that can be integrated into standard dialectical behavior therapy to treat co-occurring PTSD in BPD clients. Two women with BPD and chronic PTSD were treated and results indicate a significant improvement in PTSD symptoms as well as a variety of secondary outcomes. Despite having recent and extensive histories of suicidal and nonsuicidal self-injurious behavior, as well as ongoing low to moderate urges to engage in these behaviors, neither client self-injured or attempted suicide during the PTSD treatment. These preliminary findings demonstrate the potential efficacy of combining an exposure treatment for PTSD with standard DBT, while also showing that exposure-based PTSD treatments can be implemented safely and effectively with BPD clients. (Contains 2 tables and 1 figure.)