Ten schizophrenic and autistic children who exhibited self destructive, tantrum, echolalic, and self stimulatory behaviors were treated by reinforcement therapy. Reinforcement withdrawal, in the form of interpersonal isolation contingent upon self-destruction, and electrical shocks served to extinguish these behaviors in some children. Reinforcement withdrawal contingent upon echolalic behavior, and reinforcement delivery, contingent upon appropriate speech, were found to decrease echolalic speech. Observations led to the conclusion that as an appropriate behavior was strengthened by reinforcement, self-stimulatory behavior decreased in strength. Children learned to seek contact with adults through shock avoidance training. Establishment of speech in previously mute children was accomplished through verbal imitation training; imitation was also used to facilitate the acquisition of complex social and preschool behaviors. Because of the problem of generalization to life outside the hospital, parents were taught to employ the training procedures in the child's day-to-day environment. (LE)