About 5% of women use illicit substances during pregnancy, and approximately 22% of these also report using tobacco or alcohol. A number of treatment programs have started to offer treatment specifically designed for pregnant substance abusers. While these programs have shown some success, it is still difficult to keep these women in treatment. Brief motivational sessions have been found to improve treatment engagement and outcomes in both alcohol and drug using women. This study compares one such treatment intervention, Motivational Enhancement Therapy (MET), with standard treatment. The three individual MET sessions focus on developing rapport, exploring perceived pros and cons of using substances, reviewing the participant’s feedback on the consequences of substance use and the status of her pregnancy, and developing a change plan or strengthening the commitment to change. Patients assigned to standard treatment receive the treatment normally given in that clinic; this will include at least three individual sessions that are also designed to help them overcome alcohol and drug use.