This report is submitted to the fifth session of the Commission on Sustainable Development (CSD) to meet the critical need for a comprehensive inventory of the current state of information sources related to environmentally sound technologies (ESTs). It presents the results of an extensive Survey of Information Systems Related to Environmentally Sound Technologies carried out by UNEP over the past two years. This report extends and builds upon two previous reports on this subject submitted by UNEP to the CSD in 1995 and 1996. The goal of this effort is to identify and characterize existing and planned EST information systems and sources. The report identifies 84 such information systems and characterizes them with respect to the technologies covered, information provided, and the cost and availability of such information.