Increasingly, early childhood programs include children with disabilities and typically developing children. The purpose of this study is to examine for some aspects of early intervention / early childhood special education (El / ECSE) affect the early childhood inclusion in the United States. First, the empirical literature about activity-based intervention (ABI: Bricker, et al., 1998) underlies the practice of early intervention were summarized in order to provide a context for effectiveness of intervention / special education from early childhood. In early 1990's, with the expanding of inclusion, it was needed that the approach which suitable for practice based on the concept of inclusion, and at that time ABI approach is focused by the field of early childhood special education. ABI is ""a child-directed, transactional approach that embeds children's individual goals and objectives in routine, planned, or child-initiated activities and uses logically occurring antecedents and consequences to develop functional and generative skills (Bricker, et al., 1998, p.11)"". Second, the comparative studies of developmental and social gains of children with disabilities in integrated and segregated preschool programs were discussed to consider the place for provide an appropriate practices for children with disabilities. Third, some trend about recent naturalistic approach represented by ABI used in inclusive early childhood education setting were described. Recently, ABI and early childhood education philosophy are integrating together to produce successful inclusion for all children. In addition, it was expected that the amount of empirical studies for quality of effective inclusion as follows; ""relationship"" and ""membership"" with peers as well as consider the effectiveness of El/ECSE.