This paper reports on the conclusions of a workshop dedicated to science and data gaps in EU-funded projects relevant to water resources and water management, where over 25 EU projects were represented. Institutional and financial obstacles to data access for use in modeling exercises were identified, and gaps in scientific knowledge that contribute to uncertainty were highlighted. The paper identifies a number of sectors where these gaps often represent crucial barriers to successful research outcomes, and suggests ways and means of alleviating some of these difficulties. One approach could be through the implementation of policies aimed at ensuring free and unrestricted access to data, especially those generated by the numerous research projects that focus on issues of water availability, quality and management. Another complementary initiative could be the setting up of a centralized ‘‘clearinghouse'' for data exchange between scientists, end-users and policymakers. It is hoped that, if implemented, some of the recommendations formulated in the present paper may help pave the way for a more rapid and efficient production of research results that are of importance for policy guidance at the local, national and supra-national (EU) levels.