Recycling or reuse of waste is increasingly an imperative in the construction industry. This paper describes a research project developed to study the suitability of the use of Construction and Demolition Recycled Materials (C&DRM) as filling material of geosynthetic reinforced structures. Results of the mechanical characterization of C&DRM, the degradation induced by C&DRM on the tensile behavior of the geosynthetics, as well as, the behaviour of C&DRM/geosynthetic are presented and discussed. The main conclusions of the research project are pointed out.