Studies characterizing community populations of older people with intellectual disability (mental handicap) have frequently derived data from mental handicap registers. Such large-scale studies permit the establishment of reliable age trends, yet may utilize unreliable information and omit some individuals. Here, a functional characterization of a 50+ years sample with moderate, severe and profound intellectual disability is described, in which an extensive outreach exercise to identify individuals not known to mental handicap service providers ensured that almost 100% of people fulfilling the residence, age and ability criteria were included. Functional level, assessed by the Adaptive Behaviour Scale (ABS), is reported in relation to six factors derived from factor analysis. Overall, the sample was relatively high functioning and generally free of severe problem behaviours. There was no evidence for significant age-related functional decline.