The following research project was a comparative study of teachers in Support Units and teachers in Special Schools. They were teachers currently involved with the implementation of the 1989 NSW Department of Education Mandatory Curriculum Change for the education of students with severe intellectual disability. The purpose of the research was to present a comparative study on teachers' responses, in both educational settings, examining their understanding of the curriculum change, the concerns of individuals and the levels of curriculum usage in relation to the factors affecting implementation. The application of the Concerns-Based Adoption Model of Change (Hall and Loucks, 1987), enabled the study to focus on the various forms of the innovation, including the innovation configuration, stages of concern, and the levels of use from the two given perspectives, teachers in Support Units and teachers in Special Schools, in relation to the major factors affecting implementation. The study findings highlighted that in both educational settings, change is accomplished by individuals and is a highly personal experience, demanding adequate support by facilitators of the change through appropriate actions, in order to assist effective and successful implementation of the change.