Biebrza is a quite undisturbed lowland river of intermediate size (mean annual discharge c. 30 m3/sec) running through a valley (c. 1000 km2) containing undrained floodplains, fens and marshes and surrounded by a post-glacial landscape with ice-pushed hills, moraines and outwash plains. The Biebrza Wetlands may function as a reference for wetland restoration elsewhere. This implies that relationships between ecological variables and hydrological variables at Biebrza may help to define environmental conditions necessary for re-establishment of species and communities in restoration projects. The question we asked ourselves is: what information does Biebrza give us and how can we use this information for wetland restoration elsewhere? In this symposium an overview is given of hydrological and ecological research carried out at Biebrza. In each of the presentations the usefulness of the acquired knowledge for wetland restoration will be critically discussed.