In the present research, via the solvent casting method, Chitosan(CS)/multiwalled carbon nanotubes (MWCNTs) nanocomposite films were prepared through the use of four different percentages (1, 1.5, 2, and 2.5 wt%) of CS as polymer matrix and two percentages (0.5 and 1 wt%) of MWCNTs as ceramic reinforcement. Based on the results of TGA, it was shown that the addition of MWCNTs augmented the thermal stability of CS film. The results of XRD showed that MWCNTs induced the crystallization of chitosan film and FTIR analysis demonstrated the formation of CS/MWCNTs composite film. According to the results of tensile tests, the highest strength belonged to 2.5 wt% CS/0.5 wt% MWCNTs nanocomposite film which was increased by 176% (from 18.26 to 50.46 MPa) in comparison to tensile strength of 2.5 wt% CS film and the Young's modulus of CS/MWCNTs film increased by 195% (from 406 to 1,197 MPa) in comparison to the Young's modulus of CS film. The best film with 2.5 wt% CS/0.5 wt % MWCNTs was selected as an optimum sample for other experiments. Contact angle analysis indicated that with the addition of MWCNTs, the contact angle of CS films decreased. The results of bioactivity test showed that adding 0.5 wt% MWCNTs to CS film improved the bioactivity of CS film. Based on the biodegradability evaluation, the addition of MWCNTs to CS film reduced the degradation rate of CS film. The research illustrated the potentials of CS/MWCNTs in bone substitute. POLYM. COMPOS., 40:E1622–E1632, 2019. © 2018 Society of Plastics Engineers