In the past six years, we have successfully organized a series of international symposia on Southeast Asian Water Environment. These symposia attracted numbers of researchers, policy makers, NGO workers and graduate students in the world, where the participants exchanged impressive and invaluable body of knowledge concerning environmental issues in Southeast Asia. Now we are pleased to announce the Seventh International Symposium on Southeast Asian Water Environment, scheduled to be held at AIT conference center, Thailand from 28 to 30 October 2009. The purpose of this Symposium is to provide a forum for discussion and exchange among researchers/practitioners in Environmental Technology and Management and related areas from the Asian Region and to promote interaction among researchers from Asia-Pacific countries, Japan and other parts of the world. We do hope that, through the Symposium, a strong network or partnership with active local agents will be established, and our colleagues in Southeast Asia will be able to learn more from the experts of other countries to protect the environment of the region.