Background: Health Impact Assessment (HIA) in Ireland has developed significantly since its endorsement in the health strategies of the Republic of Ireland (2001) and Northern Ireland (2002). Throughout 2007 and 2008, research was conducted to examine HIA as a policy-informing tool throughout both jurisdictions. One aspect of this research investigated the role of local government and its relationship in advancing HIA practise and use in Ireland.Methods: A case study research design was used which employed qualitative research methods, including semi-structured interviewing and participant observation. In total 48 interviews were conducted with members of the HR steering committees and individuals closely involved in the HIAs.Results: The relationship between local government and HIA in Northern Ireland is a positive one given the strong tradition of local government in the jurisdiction. The Review of Public Administration (RPA) negatively influenced the integration of HA into local authority procedures. In the Republic of Ireland, the influence of social values and political will was found to be negatively present with the HIA on Traveller accommodation. Evidence from the HA conducted on traffic and transport in Dublin was used to plan further health promotion and community planning activities in the area.Conclusion: Local government plays a vital role in HIA practise and development in both jurisdictions. The willingness to work with external partners (such as the health care services) was an important enabler or barrier to HR operation. This will remain the case in the foreseeable future. (C) 2011 Elsevier Inc. All rights reserved.