The electromagnetic properties of ferrite filled polymer nano-composites can be determined by a classical Nicolson-Ross and Weir technique. The measurement of Sparameters makes it possible to calculate the complex permittivity ε and permeability µ of the Lanthanum Iron Garnet (LIG)-loaded polyvinylidene fluoride (PVDF )-polymer nanocomposites over the X-band waveguide. The reflection S 11 and transmission S 21 coefficients were calculated by the transmission/reflection rectangular waveguide technique. The LIG/PVDF sample, placed in the rectangular waveguide over X-band frequencies.The average values of the relative complex permittivity and permeability of LIG/PVDF over X-band frequencies [8 -12 GHz] are (4.34 -j0.09) and (1.27 -j0.15) respectively.