Context: Hydroelectric energy is considered by some to be one of the best tools we currently have for producing clean energy, but at what cost? Since the 1960s, government and private sector interest in producing several hydroelectric projects in the main stream of the lower Mekong River has increased. More recently, a plan prepared by the Mekong Secretariat in 1994 was abandoned after public opposition to the plan due to the estimated effects on the river's fisheries and the considerable number of people who would be adversely affected by the plans. Subsequently, the Mekong River Commission (MRC) signed a document in 1995 called the Mekong Agreement, which requires projects to be discussed among the four member countries, Cambodia, Laos, Thailand and Vietnam. Since 2006, interest has increased again with the government and private sector again interested in investing in hydropower in the Lower Mekong Basin (LMB). This time, they granted approval to companies to investigate 11 traditional hydroelectric dams. The MRC therefore commissioned the Strategic Environmental Assessment (SEA) of the proposed legacy dams to gain a balanced view of the risks and opportunities of the project. The final objective of the SEA was to structure the decision-making process to obtain the best outcome for the basin and the countries involved. SEA has been the evaluation method compared to Environmental Impact Assessment (EIA) due to its broader boundaries in terms of space and thematic coverage. This document takes a critical position on the Strategic Environmental Assessment (SEA) that has been conducted on these projects. The SEA was conducted for (MRC), an intergovernmental agency that works directly with relevant governments to ensure that shared water resources a. ..... middle of paper ......7010. Mekong River Commission, Bangkok.Smith, S., Richardson, J., and McNab, A., at Scott Wilson Ltd, 2010. Towards more efficient and effective use of strategic environmental assessment and sustainability assessment in land use planning. London: Department for Communities and Local Government. The ́rivel, R., and Minas, P., 2002. Ensuring effective sustainability assessment. Impact Assessment and Project Appraisal, 20, 81–91.West, C., Borzuchowska, J. and Ferreira, A., 2011. SEA application in the UK, Poland and Portugal: a consultant's perspective. Paper presented at the IAIA special conference on SEA, Prague, 21–23 September. Ziv, G. Baran, E. Nam, S. Rodríguez-Iturbe, I. Levin, S. (2012). Betting on fish biodiversity, food security and hydroelectric energy in the Mekong River basin. Proceedings of the National Academy of Sciences. vol. 109 n. 15, 5609-5614.