A set of nanocomposite film materials based on bacterial cellulose containing nanoparticles of cerium dioxide was prepared. An investigation into the structural and morphological characteristics of the films has been performed, their thermal, mechanical and tribological properties were determined. A protocol of the nanocomposite materials formation used in the work was shown to provide a homogeneous distribution of ceria nanoparticles in the matrix polymer volume in addition to the presence of certain amount of broadly size-dispersed cerium oxide aggregates in the bulk film. The increase of nanoparticles concentration in the composite provokes a progressive growth of the Young’s modulus and strength of the film material. Introduction of nanoparticles into the polymer causes the stabilization of sliding friction processes in the tribocontact with steel as well as the decrease of intensity in the wear rate of the film. An increase of the nanoparticles concentration results in a decrease of the material thermal stability.