This study evaluates the impacts of a locally based health impact assessment (HIA) on community participation, inter-sectoral and inter-agency partnership in local decision and policy-making processes. The methods comprised a series of semi-structured interviews with key informants followed by thematic analysis of transcribed responses. The study revealed a number of positive impacts among both community and service providers. A particularly advantageous impact was the facilitation of community learning through a local action group formed as a recommendation of the HIA that provided community development and HIA training. During the HIA process all participants increased their knowledge of health determinants and recognized a broader range of evidence sources for local decision-making. Participants also developed a greater understanding of each other's roles and perspectives. Additionally, the study revealed a number of barriers to HIA. Differing views on the role of HIA were evident whereby community members tended to regard HIA as an advocacy tool for local issues impacting on health in their locality, while service providers perceived its role more in terms of networking and collaboration. A key area remaining to be tackled in terms of partnership working is the approach of service agencies to enabling meaningful community participation in local decision-making processes. In this respect, attention to the cultural dimension of inter-sectoral working, and the need for training for both service agency staff and community members prior to or at the initial stages of HIA are required. Such changes could facilitate more meaningful community inclusion and help to address the current power imbalance between these two sectors.