This paper traces the evolution of the International Plan of Action on Illegal, Unreported and Unregulated Fishing (IPOA-IUU) from the expert consultation held in Sydney, Australia in May 2000, through the two technical consultations held in Rome at FAO and at COFI, to its adoption by the FAO Council in June 2001. It does not, except incidentally, enter into the substance of the provisions of the IPOA-IUU. It focuses instead on the legal context in which this voluntary instrument was negotiated, looking at some questions that arose in the course of its negotiation, such as for example the use of definitions, footnotes and addenda. It looks in particular at the relationship of the IPOA to the Code of Conduct for Responsible Fisheries, and to other International Plans of Action negotiated in the context of the Code of Conduct. It also examines the role given to international law in the IPOA, and its relationship to the 1982 LOS Convention and other international instruments.