Token economies have been applied in a wide range of settings. While there are several advantages to the use of this procedure, there are obstacles that may impede its implementation and therapeutic efficacy. These include: staff training, client resistance, circumvention of the contingencies, and non-responsiveness of subjects. Studies employing token programs with psychiatric patients, retardates, children in classroom settings, delinquents, and autistic children are reviewed. Although token economies are successful while in operation, the issue of generalization of behavior gains or resistance to extinction has not been given careful consideration. Inasmuch as generalization is perhaps the most crucial issue, several procedures are presented that are designed to facilitate maintenance of performance when reinforcement is withdrawn. Methodological suggestions for investigations on token reinforcement in applied settings are presented.