The Association of Southeast Asian Nations (ASEAN) is one of the most dynamic economic regions of the world. Its economy is linked with its diverse energy resources, high-level urbanization, and rapid industrialization. ASEAN's growing economy in the last two decades has increased the concern of sustainable development in the face of deteriorating energy security, environmental pollution, and economic hardship in energy investment. However, opportunities exist to tackle these issues. Increasing energy efficiency (both supply and demand side), exploitation of renewable energy resources (mostly hydro), and an integrated approach on energy resource management are some of the important approaches toward the sustainable energy path. Because the options are capital-intensive, cooperation and development of appropriate institutional structures and decision mechanism across the region are urgently needed. (C) 2003 Elsevier Ltd. All rights reserved.