This report aims to contribute to the debate on how best to address the risks of emerging nanotechnologies and how to promote coordinated and convergent approaches in the EU and US. It presents the main findings of a project that was carried out by a consortium of research institutions from both sides of the Atlantic: the London School of Economics and Political Science (LSE) and Chatham House (the Royal Institute of International Affairs) in the UK, and the Environmental Law Institute (ELI) and the Project on Emerging Nanotechnologies (PEN) at the Woodrow Wilson International Center for Scholars in the United States.It provides a detailed comparative analysis of EU and US regulatory frameworks in the key areas of chemicals, food and cosmetics, and identifies options and challenges for policy-makers and regulators in promoting greater transatlantic cooperation and convergence in nanomaterials regulation.