Originally main Danube basin floodplains would cover an area of 26,500 km², which is equal to about 3.3% of the total catchment size. In recent history, 80% have been cut off by dikes and dams for flood control, hydropower generation, to improve navigability or simply to meliorate land for agricultural purposes. River regulation, rectification and floodplain loss changed the hydromorphological conditions for many major rivers and cause the loss of large water retention areas, the acceleration and unfavourable superimposition of flood waves, the local increase of flood peaks and the loss of functional wetlands and their ecological services. The aim of the investigations commissioned by World Wide Fund (since 2009, three studies with increasing spatial resolution were carried out, for the whole Danube basin and for the lower Danube, Mura and Drava rivers) was the assessment and prioritisation of potential restoration areas to support national and international activities in respect to nature conservation, the ecological status improvement under Water Framework Directive (WFD) and flood mitigation. Aside of the review of existing and planned major restoration projects, new areas are proposed based on continuously available data sets including land use, spatial configuration, hydromorphological intactness, overlapping protected areas and different floodplain types.