This is a report on the application of operant condition methods to classroom discipline problems. The setting was Clara Tagg Brewer Elementary School in CLEVELAND, Ohio. The school is located in a community consisting mostly of lower-middle class black families. A few children come from a "run down" section of the community, including most of the disruptive children. The 13 regular teachers, four special teachers, and the pupils of the Brewer School were the subjects of the study. The teachers selected 33 pupils to serve as target children for study. Each of the latter was selected because of his habitual disruptive behaviors. Each teacher was asked to randomly divide target children into experimental and control groups. Operant conditioning methods were equally applied to both groups, but mediation training methods were applied only to the experimental target children. Teachers were also asked to employ other less widely known methods of experimental control, including the "multiple baseline" technique, "probes," the "reversal" technique, and the like. [Because of the print quality, parts of this document are not clearly legible.] (Author/JM)