The East-West Economic Corridor (EWEC) was launched in 1998 as a flagship initiative of the Greater Mekong Subregion. EWEC has since achieved many of its infrastructure targets and must now be transformed from a transport corridor into an economic corridor. This report reviews and updates the Pre-Investment Study for EWEC conducted in 2001. It consolidates the interests and concerns of stakeholders into a revised and updated strategy and action plan to provide a vision and framework, improve coordination, and assist in mobilizing resources for EWEC development. Preparation of this revised and updated strategy and action plan for EWEC involved a series of consultations with government officials of EWEC countries and representatives of the private sector, nongovernment organizations, and development partners. These consultations culminated in a regional workshop held on 24 April 2009 in Khon Kaen, Thailand. The revised and updated strategy and action plan for EWEC was endorsed at the 15th GMS Ministerial Conference held in Cha-am, Petchburi Province, Thailand on 17–19 June 2009.