The present background paper reflects the position of the German federal authorities on the regulation of nanomaterials (NMs) under ⁠REACH⁠. It is intended as a basis for preparing decision-making routes for political processes responses to from outsiders (e.g. Bundestag deputies or NGOs). With respect to the imminent negotiations on the regulation of NMs under REACH in the EU it is intended to explain and justify the position of the german competent authorities. This paper also deals with the regulatory need for ultrafine fibres and particles.