This study was designed to identify stable and meaningful aspects of teaching behavior pertaining to the individualization of instruction in special classes for the retarded. Ten predominantly urban classes for intermediate educable mentally retarded pupils were selected from the total of 32 such classes in a large city. These classes were observed throughout an entire school year to record the instructional interchanges between the teachers and individual children. Using the nine-category Individual Cognitive Demand Schedule (ICDS), developed for this project by the authors, a record was made for each instructional interchange of (1) the pupil involved in the interchange, (2) the principal type of level of cognitive activity called for, and (3) the type of teacher feedback given to the child's response. The teachers manifested distinctive types of individualization in their distributions of instructional communications across various kinds of cognitive activity and in the use they made of feedback. Individualizing behavior apperas to be affected by the teacher's rate of interchange, the distribution of interchanges across children in the class, and to some extent, the are of the curriculum being taught. (Author/RT)