Carboxymethyl cellulose (CMC) based bio-nanocomposite filled with graphene nano-platelets (GNPs) was prepared using casting technique. The morphology, thermal, light barrier, water vapor permeability (WVP), contact angle, moisture absorption and mechanical properties of the resulted bio-nanocomposites were investigated. The results indicated with addition of 0.5% w/w GNPs to polymer matrix, ultimate tensile strength (UTS) decreased from 7.74 MPa (in the pure film) to 5.69 MPa however, strain to break (SB) increased from 12.49% to 19.87%. The GNPs caused to reducing of light transmission and increasing of the water repelling nature of nano-biocomposites. However, it had not effect on melting point of CMC based nano-biocomposites.