The present study compared psychiatric and psychosocial functioning in 123 pregnant opiate- and/or cocaine-dependent women with and without a comorbid diagnosis of posttraumatic stress disorder (PTSD). Participants were enrolled in a comprehensive perinatal drug treatment program and completed assessments upon admission. Lifetime diagnostic prevalence of PTSD [Structured Clinical Interview for DSM-IV Disorders (SCID) confirmed] among the sample was 19%. Participants with PTSD (n=24) reported greater need for psychiatric treatment, were more likely to report a previous suicide attempt, and had more previous drug treatments than participants without PTSD (n=99). Women with PTSD were twice as likely to have lifetime Axis I and Axis II disorders and had higher rates of abuse than women without PTSD. Lifetime sexual abuse and ASI family/social composite scores were significant predictors of PTSD. Findings suggest that pregnant drug-dependent women with comorbid PTSD may benefit from specialized treatment services for trauma and/or abuse issues.