RELOOP is a project running since January 1998 and sponsored by the European Commission within the ESPRIT programme. RELOOP focuses on the electrical and electronics sector where particular need for action exists since take-back laws have been introduced or anticipated in various countries. The objective of RELOOP is the development of models and methods which supports the management of take-back logistics (TBL) and recycling chains and networks. The models and methods will be implemented in an Internet-based and Geographical Information System (GIS) based software tool providing a multi-user and multi-site trading and optimisation environment. The RELOOP software will allow a multi-criteria optimisation of TBL regarding cost, environmental impact, legislation and product design concerning recycling strategy.