During the past twenty years, an important body of research has examined the different impacts of deinstitutionalisation on the adaptation and quality of life of persons with intellectual disabilities. This empirical study was conducted with 136 persons with intellectual disabilities following the closure of the Hopital Saint-Julien (Quebec, Canada). Various questionnaires relating to adaptive and maladaptive behaviors, mental health problems, medication and to the relocation were completed. The measures were taken following the exit from institutions and subsequently after 27 months. Improvements are observed on adaptive and maladaptive behaviors, and on mental health. The relation between medication's evolution and the one noted for the maladaptive behaviors and mental health is examined. The relocation variable should be considered in future studies. (Contains 6 tables.)