The aim of this study is to identify and assess the potential environmental impacts caused by refuse-derived fuel (RDF) production from mixed municipal waste, in a mechanical-biological waste treatment plant in Krakow, Poland. The study is based on life cycle assessment methodology, employing EASETECH model. The system boundaries include only those operations which lead to the production of RDF. The adopted functional unit is 1 Mg of mixed municipal waste generated in Krakow, which enters the mechanical-biological waste treatment plant.