The relationship between cooperative learning in staff development programs and the practice of collegial interaction is examined. Thirteen administrators and supervisors from one school district participated in a staff development program that stressed a cooperative learning method. Methodology involved a comparison of participant and control group reports, participant observation, and interviews. Findings indicate that participation in the training program contributed to differences in scores between the participants and the control group. A significant program outcome was the independent formation of cooperative learning groups. Implications of the study are that collegiality improves educational leaders' skills in dealing with supervisors, peers, and staff and that staff developers must serve as models for the success of staff development programs. Six pointers for planning staff development programs based on cooperative learning are listed. (9 references) (LMI)