ABSTRACT: An integrated model approach to quantify the nitrogen loads entering the surface waters via the groundwater path is applied to the German part of the river Elbe basin. For this purpose, the results of a nitrogen balance model (Bach, Behrendt and Frede 2000), which considers the most important N-inputs to and N-removals from the soil and the groundwater residence time/ denitrification model WEKU (Kunkel and Wendland 1997; Wendland, Kunkel, Grimvall, et al. 2001) are combined. The modelled groundwater-borne nitrogen inputs into surface waters were validated using results of the MONERIS model (Behrendt, Huber, Kornmilch et al. 2000) concerning riverine nitrogen retention, nitrogen inputs from point sources as well as nitrogen inputs through direct runoff (for example, drainage).