After an overview of past researches on the inclusion of children with intellectual disabilities in general education classrooms, this article presents the results of an empirical research project on that topic. Those results show that included children with intellectual disabilities made slightly more progress in literacy than children attending special schools. No differences were found as regards the progress made by the two groups in mathematics, global adaptive behaviour and all domains of adaptive skills, with the exception of self-care skills displayed at home. Furthermore, the inclusion of children with intellectual disabilities in general education had no negative effect on the progress of their peers without disabilities in mathematics and literacy. Finally, the attitudes of teachers towards inclusion were influenced by self-efficacy beliefs, experience in including children with special needs, contacts with persons with disabilities outside of school, years of professional experience and nature of the disability.