New and emerging technologies, especially nanotechnologies with the structural uncertainties about their eventual functionalities and risks, are a challenge to governance. What is striking is how much actual governance is already occurring in and around nanotechnology without any particular actor being responsible for the emerging governance arrangements. Mapping what is happening in terms of societal agenda-building about risks of nanotechnology, including voluntary codes of conduct and calls for responsible development, allows me to flesh out the notion of de facto governance by showing how it works in the domain of nanotechnologies. This then leads me to speculate about a further governance arrangement: the internalization of requirements of ‘responsible development’ of nanosciences and nanotechnologies in actual technological and product-development choices and strategies.