Approaches to involving the public in local health care decision making processes (and analyses of these approaches) have tended to treat participation and publics uniformly in search of the ideal method of involving the public or providing the same opportunities for public participation regardless of differing socio-economic, cultural, insitutional or political contexts within which decisions are made. Less attention has been given to the potential for various contextual factors to influence both the methods employed and the outcomes of such community decision-making processes. The paper explores the role that context (three sets of contextual influences more specifically) plays in shaping community decision-making processes. Results from case studies of public participation in local health-care decision making in four geographic communities in Ontario are presented. During the study period, two of these communities were actively involved in health services restructuring processes while one had recently completed its process and the fourth had not yet engaged in one. Several themes emerge from the case studies regarding the identification and role of contextual influences in differentially shaping participation in local health care decision-making. These include the propensity for communities with different social and structural attributes to engage in different "styles" of participation; the importance attached to "community values" in shaping both the qualitative and quantitative aspects of participation: the role of health councils, local government and inter-organizational collaboration as participation "enablers"; and the politicization of participation that occurs around contentious issues such as hospital closures.