The French Environment and Energy Management Agency (ADEME) has initiated a Life Cycle Assessment (LCA) study to quantify the potential environmental impacts of electronic mail, the transmission of a 1 Mb document being the functional unit. The system boundaries comprise the manufacturing, the use and the end-of-life of all the equipment necessary to fulfill the service studied (computers, servers, routers...). The results show that the manufacturing of the computers of end-users and the use phase of datacenter equipment are the major contributors to the overall impact. The impacts of the manufacturing phase mainly come from the production of printed wiring boards while most potential environmental impacts of the use phase arise from electricity consumption of datacenter equipment used for data storage. The relative contribution of each phase varies significantly between professional and domestic users because of a more intensive use of equipment in a working environment.