Three elementary-age students with severe disabilities were moved from a special education class to an integrated (chronological age-appropriate regular education) classroom. The intervention resulted in substantial reductions in challenging behavior along with simultaneous increases in appropriate task-related and social behavior for all three students. Frequent incidences of aggression, tantrums, noncompliance, off-task and out-of-seat behavior were noted in the segregated environment. When in the integrated environment, students were observed to only occasionally engage in mild aggression (typically toward objects) and off-task behaviors, with no occurrence of tantrums or noncompliance. Results are discussed regarding the nature of special and regular education classrooms and the implications for effectively serving those students with disabilities that include challenging behavior. (Contains approximately 50 references.) (Author/JDD)