The 5th International Nano Authorities Dialogue was held from May 3 to 4, 2011 in Berlin, Germany. The main topics of discussion included the results of the NanoKommission Germany 2009-2011, as well as ongoing national and international developments in regulation, registration and information regarding nanomaterials. Hubert Steinkemper, Head of the Department at the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, emphasized the importance of addressing questions regarding regulatory tools in the governance of this emerging technology, in light of the increasing economic importance of nanotechnologies. Nanomaterials registers and nanoproduct registers, as well as the labeling of nanomaterials, were discussed as possible tools for governance of nanomaterials. Such instruments could contribute to increasing transparency about the use of nanomaterials in consumer products. A register could increase transparency, participants argued, but would not eliminate the existing uncertainties in hazard assessment. Additionally, to have such a register, there is a need for a definition of the term “nano” – a process currently underway at the European Commission. The register could be a temporary solution that could serve as a precautionary instrument, and, in case of an incident, could provide precise information about the product formulation. Participants were concerned that the labeling of “nano” could lead to a stigmatization of nanotechnologies in general, with consumers interpreting such labeling as an indication that a product could be hazardous.