Previous studies have shown that the use of behavior modification techniques, specifically the use of token reinforcement systems, can produce positive changes in the behavior of heroin addicts within a hospital setting. A token economy program was assessed to determine the effectiveness of such a program with patients in an outpatient methadone maintenance clinic setting. Target behaviors isolated for modification were patient fee-paying and appointment-keeping behaviors. Subjects were 70 patients who participated daily in a methadone maintenance clinic program. One token, a wallet-size card redeemable for future "late" doses of methadone, was awarded to each patient paying his fee on time or keeping his appointment during each treatment period. Results indicated that significantly more clinic fees were paid on time and appointments kept during treatment periods. (Author)