The  ISO International Workshop Agreement (IWA) Session #4 on “Guidance Principles for the Sustainable Management of Secondary Metals” was organised by the World Resources Forum (WRF) and the Swiss Association for Standardization (SNV) via teleconference on 15 September 2016. The main aim of Session #4 was to identify any remaining sustained or major objections to the Principles and Objectives (including Introduction and Terms and Definitions) as well as to get feedback on ‘Assurance and Traceability’ in order to move towards finalization of Version 1.0 of the Guidance Principles for the Sustainable Management of Secondary Metals by 2016. The Report summarises the main agreements reached by the participants.