The lifetime prevalence of posttraumatic stress disorder (PTSD) is about 8%-14% in the general population, and trauma victimization (51%-98%) and PTSD (up to 42%) are even more prevalent among persons treated within public-sector mental health clinics. Despite this, individuals with PTSD and severe mental illness (SMI) who are treated within the public sector tend to receive inadequate mental health services. In addition, treatments for PTSD for this population remain undeveloped, with virtually no available empirical treatment outcome data to guide clinicians. We propose a model for a comprehensive, multicomponent cognitive-behavioral treatment program for this target population that includes elements of consumer education, anxiety management training, social skills training, exposure therapy, "homework" assignments, and long-term follow-up care. Special considerations for public-sector consumers with PTSD and SMI are addressed, as are directions for future research.