AbstractHearing function of an institutionalized population with intellectual disability, consisting of 70 subjects with a mean age of 70.1 (range 60–92) years at initial evaluation, was assessed during a 10‐year longitudinal study. One subject had Down's syndrome and could not be assessed as a result of dementia. The total prevalence of mild to severe hearing loss (33.3% in the 60–70 age group and 70.4% in those over age 70) was comparable to reported data from an ageing populadon without intellectual disability in the United Kingdom (37%, respectively 60%), However, the proportion of moderate to severe losses might be higher (16.7%vs. 7% in the 60–70 age group and 33.3%vs. 18% in the older age group). Excess impairment was caused by severe congenital and childhood hearing impairment on one hand, and by conductive losses, probably caused by unrecognized chronic middle ear infections, superposed upon presbyacusis, on the other. Impacted ear wax was also a major problem. The incidence of new cases with hearing loss during follow‐up was 50%, After individual habituation training hearing aids were used without difiFiculdes by 20 out of 24 subjects. The importance of acdve screening and treatment of middle ear infections and hearing impairment from a