Background: There is currently no published research in Ireland on the health behaviours of adults with an intellectual disability (ID). With an increasing age profile and similar patterns of morbidity to the general population, the ID population would benefit from baseline data from which to establish risk factors. Methods: A questionnaire survey was carried out with 157 carers of people with an ID in the west of Ireland. Results: The results of this survey were compared with results of a health survey for the general population in the same region. The present survey found that 68% of the ID sample was overweight or obese. Levels of smoking (2.6%) and regular alcohol consumption (10.3%) were relatively low in comparison with the general population. However, participation in exercise and adherence to a healthy diet were poor. The level of resident choice and decision-making did not have any relationship to health behaviours nor did residential setting. Finally, there were no gender differences in health and lifestyle profiles. Conclusion: The results of this study have important implications for health promotion interventions for people with an ID.