This document contains the report of, and some of the papers presented at, the FAO Regional Workshop on the Elaboration of National Plans of Action to Prevent, Deter and Eliminate Illegal, Unreported and Unregulated Fishing - Southeast Asia Subregion which was held in Penang, Malaysia, from 10 to 14 October 2004. The purpose of the Workshop was to assist countries in Southeast Asia, China and the Democratic Peoples Republic of Korea to develop capacity so that they would be better placed to elaborate national plans of action to prevent, deter and eliminate illegal, unreported and unregulated fishing (NPOAs-IUU). The Workshop addressed the 2001 international Plan of Action to Prevent, Deter and Eliminate Illegal, Unreported and Unregulated Fishing (IPOA-IUU) in detail and the Technical Guidelines that have been developed to support the implementation of the IPOA-IUU; concepts of planning and the elaboration of action plans; a case study for the development of a NPOA-IUU; and decision-making about IUU fishing and school enhancement through the identification of key issues related to the NPOA-IUU, the primary vehicle by which the IPOA-IUU will be implemented by countries. Working groups were formed to encourage maximum participation in the Workshop. A review of the major IUU fishing problems in the region and their possible solutions were discussed.