The present paper is concerned with the effect of cork and rice husk ash micro particles fillers on the mechanical properties (flexural resistance, fracture toughness, impact absorbed energy, elastic and viscous moduli) of polyester based composite. Composite sheets were hand molded using weight filler fractions of 1, 2.5, and 5 %. Flexural strength of filled materials was much lower than the polyester matrix, with more pronounced effect for cork powder, decreasing significantly with filler content increases. Fracture toughness decreases also on the filled composites. Using cork powder fracture toughness decreases significantly when filler content increases, while for rice husk ash filler a slight increase was observed. Both fillers improve absorbed impact energy, peaking at about 2.5 % of filler content. Best improvements were obtained using rice husk ash powder, reaching about 30 %. Both fillers increase glass transition temperature and the maximum use temperature and also the elastic modulus compared with polyester. It can be concluded from this study that the used agro-waste materials are attractive reinforcements from the standpoint of their mechanical properties.