The misbehavior of children often presents a severe problem to the classroom teacher. An attempt is reported here to eliminate such misbehavior by strengthening a competing and educationally relevant class of behavior, namely academic performance. A classroom was sleected in an urban school which included children with the most severe behavior problems. Fourteen children, ages 6 to 9 years, were included in this study. A simple but reliable method for recording the behavior of the teacher in the classroom was first developed; the emphasis in the recording was placed on objective definition and quantification of behavior relevant to academic performance in the classroom. Through training in behavioral procedures, the teacher was able to eliminate the behavior problems while increasing her effectiveness in the classroom as measured by (1) the proportion of time per day spent discussing academic subject matter with the class; (2) the daily number of assignments given to each pupil; and (3) the proportion of correct work performed by the pupils. The increase in academic achievement by the students and the increase in teaching time by the teacher occurred in a matter of 4 academic days. An additional findings was that 6 out of the 14 children were promoted to the regular classroom following the behavioral intervention. (Author)