The main objective of this paper is to combine and integrate environmental, economic and social impact assessment procedures in order to support decision-making in the context of flood control policy in the Netherlands. The hydraulic, hydrological, ecological, economic and social effects of alternative flood control policies, such as land use change and floodplain restoration, are evaluated using a combination of advanced quantitative modelling techniques and qualitative expert judgement. The results from the ecological, economic and social impact assessment are evaluated in an integrated way through cost-benefit analysis (CBA) and multi-criteria analysis (MCA). As expected, these methods produce different outcomes. Although traditional flood control policy-building higher and stronger dikes-is a cost-effective option, investment in alternative flood control policy-land use changes and floodplain restoration-can be justified on the basis of both CBA and MCA when including the additional ecological and socio-economic benefits in the long run. The outcome of the MCA appears to be especially sensitive to the inclusion of the qualitative scores for the expected social impacts of land use change and floodplain restoration. An important research question remains how to assess, integrate and trade-off (1) significantly different types of impacts in a methodologically sound way in both cost-benefit and multi-criteria analysis, and (2) significantly different types and quality of available knowledge and information about these impacts. © 2004 Elsevier B.V. All rights reserved.