This report presents the results of the first global assessment of transboundary river basins, prepared in partnership with UNEP-DHI (lead), the International Union for the Conservation of Nature, the Stockholm International Water Institute, Oregon State University, The City University of New York Environmental CrossRoads Initiative, the International Geosphere-Biosphere Programme, Columbia University Center for International Earth Science Information Network, the Delta Alliance, and the University of Kassel Center for Environmental Systems Research.