This report is one of the outputs of the Vulnerability Assessment of Freshwater Resources to Environmental Change project, presenting a situation analysis with regard to the vulnerability of water resources system in South East Asia. In addition to the more general South East Asian water issues addressed herein, the report considers Mekong River Basin in detail as a case study. Though the Mekong River Basin (MRB) is currently not characterized by either water shortages or open conflicts, it warrants attention due to the potential future threats that might arise from development pressures and transboundary issues.