The WOSAP focuses on addressing the substance abuse problems of women offenders. The program offers three modules: (1) an Engagement and Education (E & E) group offered to all institutionalized women regardless of identified substance abuse problems; (2) an Intensive Therapeutic Treatment (ITT) group for women offenders with severe to moderate substance abuse problems; and (3) a Relapse Prevention and Maintenance (RPM) group to address problematic behaviors relating to crime. Evaluation results revealed that the WOSAP had a positive impact on all areas evaluated by the study, including an increase in knowledge of the impact of substance abuse in several life areas and an increase in motivation to change. Examinations of the severity-of-substance-abuse measures indicated that women were appropriately assigned to the ITT module, with 95 percent of the ITT group reporting moderate to severe substance abuse problems. The E & E group had a completion rate of 93 percent and the more severely impacted women progressed to the ITT group, suggesting the program attracted the intended targeted groups. The ITT group had an 82 percent completion rate and a high participant satisfaction rate. The interim evaluation assessed the first 7 months of the WOSAP’s implementation. The evaluation compared 3 study groups: (1) an E & E only group consisting of 148 female offenders; (2) an ITT group consisting of 45 female offenders; and (3) a comparison group consisting of 269 female offenders who did not participate in the WOSAP. Data on offenders were obtained from the Offender Management System and included pre- and post-test assessments. Self-reported information was collected via semi-structured interview prior to participation in ITT. The next stage of the WOSAP evaluation will examine whether the women participants were able to sustain the changes they made in terms of decreased drug use and reduced criminal recidivism. 4 tables, 15 notes