There is an increasing demand for improvement of the quality of decisions about flood risk mitigation by fostering public participation in decision-making. However, the extent and way in which formalized participation guarantees good outcomes is still a matter of discussion. This article analyzes different approaches to decision-making for flood risk mitigation by comparing two experiences in the Italian Alps. In Vipiteno-Sterzing, decisions were made by involving citizens in a structured participatory process. In Malborghetto-Valbruna, a formally technocratic (yet substantially inclusive) approach was adopted after the flood that affected the municipality in 2003. Our results critically review the perspective that structured participation is always something “good.” In this regard, the way relevant trade-offs between public and private goods were acknowledged and dealt with turned out to be crucial. At the same time, effective participation is closely related to citizens’ actual engagement, institutional responsiveness to residents’ needs and expectations, and the capacity to harmonize different views and types of knowledge in the development of risk mitigation options. Policy context, choice of approach and quality of outcomes appear as “nested” issues. Further research is needed in order to assess different experiences of decision-making and to set robust conditions for better outcomes in public participation.