Considering the public perception of risks with regard to technology controversies has increasingly become important since the debates on genetically modified organisms (GMOs) in Europe. The perception of risks by the population is not comparable with assessments by experts as the concerns stem from a possible direct effect on citizens’ lives, thus subject to different dynamics. This dossier focusses on factors which influence the public perception of risks and elaborates on their relevance for regulatory policies. Moreover, it introduces several European studies on familiarity and risk perception of nanotechnology. The studies’ results are similar: While citizens know comparatively little about nanotechnology, the questioned subjects also perceived it as having a relatively low risk potential. There are several possible explanations: Alongside a general technology-friendly attitude, positive media reporting and the broad range of the technology – which makes it difficult to scandalize it as a whole -, a basic trust in institutions concerned with risks and an accurate, proactive regulatory policy could play an important role.