Methylcellulose (MC)-based films were prepared by casting from its 1% aqueous solution containing 0.5% vegetable oil, 0.25% glycerol, and 0.025% Tween 80. Puncture strength (PS), puncture deformation (PD), viscoelasticity coefficient, and water vapor permeability (WVP) were found to be 147 N/mm, 3.46 mm, 41%, and 6.34 g.mm/m(2).day.kPa, respectively. Aqueous nanocellulose (NC) solution (0.1-1%) was incorporated into the MC-based formulation, and it was found that PS was improved (117%) and WVP was decreased (26%) significantly. Films containing 0.25% NC were found to be the optimum. Then films were exposed to gamma radiation (0.5-50 kGy), and it was revealed that mechanical properties of the films were slightly decreased after irradiation, whereas barrier properties were further improved with a decrease of WVP to 28.8% at 50 kGy. Molecular interactions due to incorporation of NC were supported by FTIR spectroscopy. Thermal properties of the NC-containing films were improved, confirmed by TGA and DSC. Crystalline peaks appeared due to NC addition, found by XRD. Micrographs of films containing NC were investigated by SEM.