Nanocomposite films comprising of ion-conducting polymer electrolyte, multi-walled carbon nanotubes (MWCNT) as the electron-conducting network and ceramic (BaTiO3) as ferroelectric nanofiller have been synthesised for electromagnetic shielding application. XRD and dielectric studies of the synthesised BaTiO3 nanoparticles show a tetragonal structure and ferroelectric nature. The incorporation of nanofillers (MWCNT and BaTiO3) in the polymer electrolyte enhances the conductivity and dielectric property of the nanocomposites. Polymer nanocomposites with 7.5wt% of BaTiO3 nanoparticles have exhibited the highest shielding effectiveness (SET)similar to 81dB in the X-band (8-12GHz). This enhancement in SE can be attributed to the (1) formation of micro-capacitors and interconnected network provided by MWCNTs, (2) spontaneous polarisation of BaTiO3 and its volumetric effect on the polymer nanocomposites and (3) leakage current due to the ions of the electrolyte which results in dielectric loss.