This bulletin presents an overview of prevalence of intellectual disability and its related impairments, health conditions and activity limitations. People with an intellectual disability represent a very significant client group of disability services in Australia, reflecting the priority given to this group and the origins of many disability services in Australia. This bulletin presents an overview of prevalence of intellectual disability and its related impairments, health conditions and activity limitations. The analyses focus on outcomes of participation in major life areas in children and young adults with intellectual disability as well as people ageing with intellectual disability.