The seminar on Problem Formulation for the Risk Assessment of Biopesticides was organised by the OECD Expert Group on Biopesticides and was held in February 2024. The topics discussed included the history and principles of Problem Formulation, its application in regulatory approaches and specific case studies. Additionally, an overview of the challenges, considerations and potential solutions in harmonising Problem Formulation for biopesticide risk assessment was provided. The seminar's primary outcome was identifying the need for collaboration and discussion to develop Guidance on Problem Formulation for biopesticides.