BackgroundThe cost of caring for people with intellectual disability currently makes up a large proportion of healthcare spending in western Europe, and may rise in line with the increasing numbers of people with intellectual disability now living to old age.AimsTo report service use and costs of older people with intellectual disability and explore the influence of sociodemographic and illness-related determinants.Methodwe collected data on receipt and costs of accommodation, health and personal care, physical as well as mental illness, dementia, sensory impairment and disability in a representative sample of adults with intellectual disability aged 60 years and older (n=212).ResultsThe average weekly cost in GBP per older person was 790 pound (41 pound 080 per year). Accommodation accounted for 74%. overall costs were highest for those living in congregate settings. Gender, intellectual disability severity, hearing impairment, physical disorder and mental illness had significant independent relationships with costs. mental illness was associated with an additional weekly cost of 202 pound.ConclusionsOlder adults with intellectual disability comprise about 0.15-0.25% of the population of England but consume up to 5% of the total personal care budget. Interventions that meet needs and might prove to be cost-effective should be sought.