The UNECE Task Force on Water and Climate, chaired by the Dutch Ministry of Infrastructure and Water Management and the Swiss Federal Office for the Environment, has led the development of a Guidance on Water and Adaptation to Climate Change to guide countries in developing a joint adaptation strategy. The Guidance is a collaborative achievement: more than 80 experts from national authorities, academia, non-governmental and international organizations contributed to its preparation. It builds on the principles of the UNECE Water Convention and on the experience gained in its implementation. The Guidance places special emphasis on the specific problems and requirements of transboundary basins, with the objectives of preventing, controlling and reducing transboundary impacts of national adaptation measures and thereby preventing and resolving possible conflict. The Guidance also underlines the benefits of cooperation in adapting to climate change in transboundary basins: sharing the costs and benefits of adaptation measures, better managing uncertainty through the exchange of information, broadening the knowledge base, and enlarging the range of measures available for prevention, preparedness and recovery, thus allowing us to find better and more cost-effective solutions.