It seems to be increasingly recognised worldwide that the aims of nature conservation or of regional planning can only be achieved with adequate involvement of the concerned communities themselves. This article analyses the social processes during the proposed extension of the Swiss National Park between 1996 and 2000 from a participatory viewpoint. It is based on an analysis of relevant newspaper articles and in-depth interviews with representatives of involved stakeholders. Considering that participation is a very popular, yet contested term, we distinguish between normative (i.e., the aim is participation) and instrumental (i.e., the aim is to achieve predefined goals) participation, notions that supplement rather than exclude each other. While the local population rejected the majority of the proposed extensions of the Park, results show that this should not be perceived as a failure of the process. That the outcome was not perceived by local people to be satisfactory could be explained by the lack of awareness of the basic principles of participatory processes, like openness and transparency of planning, a sufficient timeframe, and independent mediation. These organisational shortcomings resulted in fundamental opposition from groups of local stakeholders and constrained the future development potential of the region.