Abstract - This work is aimed to the production of new green composite materials based on a water soluble polymer, PVA, and different natural fillers. Two natural additives, such as shredded walnut shells and mixed food waste, were used to produce bio-composite systems. Both additives, deriving from food industry wastes, were added in a PVA/water solution, which allowed to produce samples by the use of a pressure free process. Rheological analysis was performed in order to study the evolution of the material viscosity during thermal treatment, aimed at water removal. Samples obtained were characterized by means ofdifferential scanning calorimetry (DSC), showing an improvement of the glass transition temperature brought by the addition of walnut shells. Finally, flexural tests were carried out on samples obtained after the incorporation of the different additives in PVA and compared with the mechanical properties of the neat matrix. Results obtained indicate the potential improvement brought by the addition of walnut shells, which allow to increase the flexural modulus, at the expenses of a reduction of flexural strength.