There are limited studies on the prevalence of epilepsy and co-morbid conditions in older adults with an ID. To begin to address this prevalence of epilepsy was estimated for participants in the Intellectual Disability Supplement to the Irish Longitudinal Study on Ageing. Associations with demographic variables and co morbid health conditions were examined. It was found that prevalence was high (30.7%); but declined as people aged. Those with epilepsy were less likely to live with family, independently or in community settings, rates of refractory epilepsy were high and, despite medication over half of those with epilepsy still reported experiencing seizures. Given these findings, people with ID and their careers have considerable needs for information about epilepsy management, and for support from specialist ID and epilepsy services.