'Closed loop' end-of-life strategies such as remanufacturing must be applied to create eco-efficient products. Remanufacturing may be a key element in reducing the environmental impact of products but this remains to be proved. The aim of this study is to help designers evaluate the environmental impacts of their remanufacturing process during the design phase. The first task is to identify, list and classify the various remanufacturing processes (disassembly, cleaning, sorting and controlling, reconditioning, reassembly) by type of process and then estimate the environmental impact for each process. These processes are then formalized by characterization and organised in a database. Using a simulator, the different processes can be aggregated to assess the environmental impacts of a remanufacturing line. An example is presented in the last part of this paper to illustrate the proposal.