Co-morbidity between posttraumatic stress disorder (PTSD) and substance use disorders (SUD) is high and there is a need for empirically validated treatments designed to address PTSD among SUD patients. One effective PTSD treatment that may be useful in treating PTSD-SUD is exposure therapy. This paper reviews the relationship between comorbid PTSD and SUD, the basics of exposure therapy for PTSD, and reviews preliminary work assessing the utility, safety, and tolerability of exposure therapy for PTSD-SUD. Although more research is needed, preliminary studies suggest that exposure therapy for PTSD-SUD is safe and tolerable and shows promise as an efficacious treatment.