The effects of teacher-delivered social reinforcers on the task ersistent behavior of children enrolled in an intermediate class for the efucable mentally retarded were studied. These children were grou ed with a regular fourthgrade class during a social studies period in whici the study was conducted. The special education children were randomly divided into two groups, with seven children in each group. Using a reversal design, social reinforcers were delivered contingent upon the task persistent behavior of the seven target children. The seven youngsters in the control, or nonreinforcement, group were essentially ignored as they engaged in appropriate task-related behaviors. The results clearly show that increases in the level of task persistent behavior and the administration of social reinforcement were functionally related. The level of task persistent behavior emitted by the control children was not affected by reinforcement delivered to their peers.