In our previous work, the lanthanum iron garnet-filled PVDF-polymer nanocomposite has been prepared. The reflection and transmission coefficients (S-Parameters) of PVDF-13 LIG were measured using rectangular waveguide in conjunction with a microwave vector network analyzer (VNA) at X-band frequencies (8-12 GHz). In order to determine simultaneously the real and imaginary parts of complex permittivity and permeability of nanocomposite sample the Nicholson-Ross-Weir (NRW) method was applied based on the measurement of the S-Parameters of the materials. The general observations of the results indicate that the decreasing in real and imaginary part of complex permeability and real part of complex permittivity resulted in increasing the frequency; meanwhile imaginary part of permittivity tends to become constant when frequency increased. © 2012 Elsevier Ltd. All rights reserved.