The purposes of this study were as follows: (1) to investigate the prevalence of maladaptive behaviors of 157 retarded children living in a public instiution, and (2) to examine the effects of the token economy program on decreasing maladaptive behaviors of 24 retarded individuals selected from that institution. Information on behavior problems was obtained using selected items from the Adaptive Behavior Scale (ABS), and was rated by special class teachers or day care personnel. Single-case experimental design was employed. Results showed that the prevalence of maladaptive behavior among 157 retarded children was 78.4%. The most frequent problems among the clients were: inappropriate interpersonal manners (36.3%), unacceptable vocal habits (30%), psychological disturbances (30%) , withdrawal behavior (28.7%), and rebellious behavior (27.4%) - With some exceptions, combining token economy and other behavioral techniques (e.g.,DRO, DRI, or overcorrection etc.) had resulted in effective reductions in a variety of maladaptive behaviors, such as hyperactivity, stereotyped behavior and self-injurious behavior. From these results, it is suggested that continuous training of longer duration should be implemented in order to maintain its long-terms effect.