An electromagnetic interference (EMI) shielding material based on the composite of BaFe 12 O 19, polyaniline (PANI) and multi-walled carbon nanotube (MWCNT) was proposed. The constituents of the composite were brought together through mechanical mixing and the in-situ polymerization of aniline on the BaFe 12 O 19 and MWCNT surfaces. A series of composite with different MWCNT wt% loadings (0, 5, 10, 15, 20 and 25wt%) was prepared, and its effect on the EMI shielding performance was investigated. X-ray diffraction analysis was performed on all synthesized composites to confirm the phase formations. FESEM micrographs reveal the PANI particle formation on both BaFe 12 O 19 and MWCNT surfaces. Electromagnetic measurements were done by using a rectangular waveguide connected to a network analyser to obtain the permeability, μ r, permittivity, ε r, and shielding effectiveness (SEA and SER). The increase in the MWCNT loading results in the enhancement of the composite's shielding performance to a certain limit. Optimum EMI shielding performance are shown by sample PBM4 (20wt% MWCNT) with SER and SEA values of 5.14 dB at 8.2 GHz and 36.41 dB at 12.4 GHz, respectively. influence of different MWCNT loadings (0, 5, 10, 15, 20 and 25wt%) on the EMI shielding performance of a composite consisting of BaFe 12 O 19, polyaniline (PANI) and multi-walled carbon nanotube (MWCNT) were investigated.