Ecological Sanitation (EcoSan) is an environment friendly sustainable sanitation system which regards human waste as resource for agricultural purposes and food security. In contrast to the common practice of linear waste management which views waste or excreta as something that needs to be disposed, EcoSan seeks to close the loop of nutrients cycle, conserve water and our surrounding environment. In other words, EcoSan is a system that prevents diseases, protects the environment and recovers & recycles nutrients and organic matter from waste materials. The most common form of EcoSan is the urine separating toilets which collect urine and feaces separately and recycles them as organic fertilizer. This manual is designed for professionals interested in promoting EcoSan in Nepal and other developing countries. It briefly explains the basic concepts of EcoSan and its application in Nepal, and provides technical details on different types of EcoSan toilets. The main objective of this manual is to assist in introducing and scaling up ecological sanitation as an approach to environmental sanitation.