Increasingly, mentally retarded adolescent offenders are being diverted into community-based residential treatment. Thus, many of these aggressive youths, who would previously have been institutionalized are now diverted into available group home settings. Implementing restrictive aspects of treatment regimens with this population frequently evokes intense escape/avoidance behaviors which cannot be controlled at those open sites. As a result, in traditional group homes these adolescents readily avoid therapy, run away recurrently, and thus pose serious risks to themselves and the community. The authors describe two secure group home designs which seem to promote consistent treatment of this difficult population, while protecting the local community. Preliminary evidence is presented indicating that these specially designed environments are essential adjuncts to the initial phase of treatment of mentally retarded adolescent offenders.