La réglementation concernant l'épandage des boues de station d'épuration a été récemment renforcée afin de garantir la qualité de cette filière. Des exigences particulières ont été définies concernant l'auto-surveillance des producteurs de boues de station d'épuration. Afin de renforcer la traçabilité des opérations une méthode a été mise au point par le Cemagref, utilisant à la fois le GPS et un système d'information géographique. Ce système permet de valider le registre des opérations et de gérer l'ensemble des données nécessaires au suivi. / Regulations concerning sludge spreading have been recently reinforced in France. Each water waste sludge producer has to build up a spreading schedule which determines the spreading locations in agriculture, according to soil characteristics and environmental hazards. This schedule is submitted for agreement to local authorities. Then, each year, a record of spread areas, sludge quantity, and sludge content analysis will be transmitted to the same authorities. In some cases, GIS is now used for the management of both spreading plan and yearly record. Using a G.I.S. makes easy to compare the effectively spread areas with the planned locations. By using a G.P.S. we are sure to obtain the real location of each spread area, and we may also directly get a standard file that can be easily transferred to G.I.S. This paper defines the necessary requirements concerning G.PS. performance. An 8 channel D.G.P.S. with a real time correction from geostationary satellite was selected. A program has been developed in order to create vectorial files from recorded G.P.S. positions. These files use French coordinates for cartographic positions (Lambert 2). A method for saving associated data was also developed in order to identify each vectorial file and increase information on the work done. Finally, we have defined an organisation that may transfer information between the different people involved in the system. The cost of this system has been compared to total cost of spreading operations and was found very low when shared between all the inhabitants of a city using a waste water plant.