Statistical information on the numbers of drug abusers in prison and the extent of their drug misuse has been obtained through special inquiry reports, court records, inmate self-reports, and urine testing at admission. Evaluation studies indicate that inmates completing drug treatment programs at particular prisons had lower recidivism in followup studies than did inmates whose treatment was not completed. Evaluation of inmate sojourns in drug therapeutic communities outside prisons showed a statistically significant reduction in the number of persons and the number of days in prison for the following subgroups: offenders satisfactorily completing treatment in therapeutic communities, offenders satisfactorily completing family care, interrupted cases in family care, and offenders satisfactorily completing other treatments. Studies indicate that although urine testing can be a useful control instrument, there are a number of problems associated with its use. Studies show the effectiveness of special training for prison staff in handling inmate drug abuse. 9 references.