The current study presents case reports of six children diagnosed with autism spectrum disorder (ASD) who received intensive applied behavior analysis within the Comprehensive Application of Behavior Analysis to Schooling (CABAS[R]) system and successfully integrated into mainstream education. The participants' interventions followed curricular objectives from the Preschool Inventory of Repertoires for Kindergarten (PIRK[R]), an empirically validated assessment tool and curriculum which improves outcomes for children with ASD and prepares for mainstream integration. Each case study presents acquisition of curricular objectives, rates of learning annually and results of independent psychological measures throughout the intensive behavioral intervention. This paper examines the variables (age of treatment onset, duration of treatment, presence of stereotypy or challenging behaviors prior to treatment) which may have influenced the successful integration of these participants into mainstream education settings. (Contains 2 figures.)