There have been fundamental changes in the way children and adolescents with mental retardation are viewed and treated. And, in the years to come, we will see significant advances in treatment and prevention efforts that will be unprecedented in the history of this field. Leading the way will be biomedical discoveries about the nature of the differing forms of mental retardation and our ability to intervene. This paper discusses some of these trends, including the impact of the mapping of the human genome and advances in functional genomics and functional proteomics on interventions for genetic disorders. Additionally, the potential roles for behavior therapists in both biomedical as well as behavioral treatments are outlined. It is argued that behavior therapists must play a central role in each of these areas in order to ensure successful implementation and dissemination.