The Intergovernmental Science-Policy Panel on Chemicals, Waste and Pollution (ISP-CWP) is being established amid growing pressure on global science-policy institutions and disagreements among Member States over how they should operate. This memo examines three issues that will be central to the Panel’s effectiveness: legitimacy and participation, the engagement of experts and the focus and function of its assessments. It considers how the Panel can build broad participation, draw on diverse sources of expertise and produce assessments that provide relevant, solutions-oriented evidence for policymaking.