In this paper, the integration of mediated modelling (MM) techniques with multi-criteria assessment (MCA) in a Participatory decision-making context is discussed. We briefly present the major features of MCA, of system dynamics methodology, and of group model building techniques. The application of MM in a Participatory exercise is illustrated by a Case Study developed in a protected coastal wetland (Ria Formosa, Portugal). Possible avenues to integrate MM into multi-criteria decision making in the framework of sustainable development issues are discussed. (c) 2004 Elsevier Ltd. All rights reserved.