Women with current posttraumatic stress disorder (PTSD) comprise 30-59% of substance abuse treatment samples and experience a more severe course than women with either disorder alone. As yet, no effective treatment for this population has been identified. This paper reports outcome results on 17 women who completed a new manual-based 24-session cognitive behavioral group therapy protocol treatment, based on assessments at pretreatment, during treatment, posttreatment, and at 3-month follow-up. Results showed significant improvements in substance use, trauma-related symptoms, suicide risk, suicidal thoughts, social adjustment, family functioning, problem solving, depression, cognitions about substance use, and didactic knowledge related to the treatment. Patients' treatment attendance, alliance, and satisfaction were also very strong. Treatment completers were more impaired than dropouts, yet more engaged in the treatment. Overall, our data suggest that women with PTSD and substance abuse can be helped when provided with a treatment designed for them. All results are clearly tentative, however, due to the lack of a control group, multiple comparisons, and absence of assessment of dropouts.