Background: The experiences of older parents of adults with Asperger syndrome have not been explored in the research literature. Method: Four families who had middle-aged offspring with Asperger syndrome were interviewed (3 mothers and 1 couple), and the interviews were analysed using interpretative phenomenological analysis (IPA). Results: Six themes emerged from the analysis: (a) providers of "hidden" support, (b) role of advocate, (c) social isolation, (d) intrafamilial relationships, (e) support for parents, and (f) future concerns. Conclusions: The findings of this study offer insight into the experience of parents of adult sons with Asperger syndrome. Implications for future support interventions and research are suggested. (Contains 1 table and 1 note.)