Despite a long-standing tradition of institutional placement in Switzerland, many older adults with intellectual disabilities continue to be supported by aging parents and siblings. For various reasons, these carers and the adults concerned have been overlooked up to now. To find out how many such families are providing housing and care of this kind, and what characterizes such family units in French-speaking Switzerland, a university-level training center undertook a study of this population. Qualitative information was obtained through questionnaires and interviews, providing information on the family history, the types of care which the families currently provide, and their short- and long-term needs. The results suggest that in the Cantons concerned, 27% of adults with intellectual disabilities aged 35-64 reside with family carers, 80% of the latter being elderly parents among whom 16% are aged 77 or older. The adults involved are relatively autonomous, requiring direct assistance only for complex tasks. Some 88% participate in day activities including employment in ordinary settings. In general, expectations for the future do not include residence in congregate care; furthermore, the current network of residential services is insufficient to accommodate this population's members as they age. The authors conclude that local social services providers must plan for enhanced community services to accommodate this growing group in the years to come. (Contains 2 footnotes, 5 tables, and 1 figure.)