The recent reform of the European water policy recognizes the importance of developing effective mechanisms to support public and stakeholder participation in river basin decision-making processes. This paper critically reviews the evaluation processes of different types of water related project in five European countries (Portugal, Greece, The Netherlands, the United Kingdom and Spain), with respect to participatory criteria. The horizontal comparison of these cases accounted for criteria such as the political and institutional context, the design, the implementation and the evaluation of the outcomes of participation. The results indicated that, in the majority of the case studies, participation was simply adopted to conform to the requisites of the Environmental Impact Assessment Directive. Thus, there was truly no room for the active involvement and collaboration of the interested parties. The development of guidelines, drawing from the analysis of past experiences, is expected to support the implementation of the participatory objectives of the EU water policy. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.