In this paper we present a study on the microwave frequency properties of PVC/Fe3O4 composite nanofibers, with different amounts of iron oxide nanoparticles incorporate in PVC matrix. Using electrospinning where obtained composite nanofibers with diameters ranging between 100 nm and 600 nm. The transmission loss of PVC/Fe3O4 composites measured in the microwave frequency range of X-band were found to be below - 15 dB demonstrating that these materials can be used as protection material of electromagnetic radiation. The applied magnetic field significantly modifies the measured scattering parameters in our samples case in a rather large domain of values for the field. (C) 2011 Elsevier B.V. All rights reserved.