This report summarizes lessons learned from implementing Environmentally Sound Technology (EST) pilot projects by the International Environmental Technology Centre of UNEP Division of Technology, Industry and Economics (UNEP-DTIE-IETC). The document aims to inform national level mainstreaming of the EST pilot project results, and provides lessons learned for decision-makers in national governments and for international technical cooperation personnel. The featured projects were conducted within three pillars of IETC's focal areas. They are: Support for Environmental Management of the Iraqi Marshlands project in the water-sanitation pillar; Integrated Solid Waste Management project in China, India and Lesotho under the waste management pillar; and ESTs for Building waste Reduction in Indonesia (DEBRI) project under the disaster management pillar. Each project and cross-cutting lessons learned focus on six areas, which are project management structure, governance, capacity building, EST implementation, financing, and local conditions/infrastructure.