A total of 2,646 inmates participated in one or more substance abuse treatment programs, with a completion rate of 55.9 percent. They had an average age of 29.3 years and a 10th grade education and spent an average of 9 months in society before their recommitment. This treated group included 2,118 males and 528 females. Inmates who participated in FDC treatment programs had a 26-percent rate of recommitment, compared to their untreated counterparts, who had a 36-percent rate. This gap was substantially larger when inmate age was controlled as a factor influencing return to the prison system. When untreated inmates within the same-age category as treated inmates were selected as a group, their rate of recommitment was 40 percent. The difference of 14 percent between the two rates of recommitment was an encouraging outcome for the treatment programs. It was also found that treated inmates, although having a lower rate of recommitment, tended to stay out of prison for a shorter period of time. The average length of time out of prison before recommitment was 9 months for the treated group and 14.4 months for the untreated group. This discrepancy was attributed to lack of support and relapse prevention in the inmates' communities. 10 tables