Although the presence of intellectual disability (ID) per se is not usually regarded as a health problem, the biopsychosocial implications of cognitive impairment contribute to the vulnerability of adult patients with ID in any healthcare system. The adult patient with ID differs from a patient in the general population in terms of health determinants, morbidity and mortality profiles, and in the ability to access quality healthcare. These differences represent a risk for adverse health and well-being outcomes in this population, and for increased costs of health services, particularly in the hospital setting. This paper focuses on addressing the issues facing the adult patient with ID, their caregivers, and health professionals, specifically in the setting of secondary and tertiary level healthcare systems. The authors argue that a specialist hospital service for adults with ID urgently needs to be established in major public hospitals along the lines of a paediatric model. The model of existing paediatric developmental disability units within hospitals is an example of a successful specialised system of care within a generic system. The authors propose that a similarly designed system of specialised care for the adult patient with ID also be introduced into the generic adult hospital system. (Contains 1 table.)