Students with severe and multiple learning difficulties have traditionally been excluded from mainstream education. Three arguments are put forward for integrating these students: social and humanitarian motives; interpretations of the 'least restrictive environment' as one in which interactions with non-disabled peers are least restricted; and a changing concept of education to include a range of functional skills which provide preparation for adult life. Ways of implementing integration are discussed, including location of special classes in regular schools, integration into regular classes, and partial integration through links between regular and special schools. Although many existing integration programmes appear promising, there has been little systematic research in the area and few attempts at independent evaluations. Fears about potential loss of support services in integration appear to have some justification. Fears about adverse behaviour by non-disabled peers have proved to be largely unfounded, but opportunities need to be deliberately structured to ensure that positive interactions occur between integrated students and their peers. Long-term outcomes for students with severe and multiple learning difficulties integrated into regular schools have not been considered.