Understanding public perceptions of and attitudes to nanotechnology is important in order to understand and facilitate processes of dialogue and public participation. This research quantitatively analysed risk perceptions and attitudes of Dutch science café participants (n = 233) and compared these with members of the Dutch public (n = 378) who had not attended a café but were interested in science and technology as well. A qualitative analysis of the meetings contextualised and enriched the quantitative findings. Both groups shared similar key attitudes and were positive about nanotechnology while the Dutch café participants were even more positive about nanotechnology than the group of non-participants. The perception that nanotechnology would lead to risk applications was only predictive of attitudes for the non-participants. The qualitative analysis showed that café participants and speakers considered discussion of the risks, benefits and related issues important. Further research could investigate how science cafés can play a role in the science–society debate.