The 44 male clients, divided into groups of between 8 and 12, were all documented or self-reported substance abusers who volunteered for the program. The subjects, inmates at the Baltimore City Jail, were demographically similar to the nationwide incarcerated population. The three evaluation materials developed for this study included a questionnaire, administered before and after the program; client rating forms; and group leader rating forms. The effectiveness of program implementation was assessed using process and outcome evaluations. The findings indicated that, while the program was effective in increasing client knowledge of drugs and alcohol, modifying their attitudes toward substance abuse, and providing social skills training, it was not as effective in increasing knowledge of stress management skills. Jail officials, group leaders, and clients all reported the program was successful in fostering positive attitudes. These preliminary findings suggest that a social competence approach to inmate drug rehabilitation programs holds promise for future development. 5 tables and 12 references