Carbon fibers were prepared as an electromagnetic interference shielding material by electrospinning and heat treatment methods. To increase the electromagnetic shielding effectiveness, additives (Fe2O3/BaTiO3/multi-walled carbon nanotubes) were included due to their excellent dielectric and coercive force properties. The additives were observed to cluster on the surface of fibers; additive metal oxides did not show any structural changes during the heat treatment, retaining their original magnetic properties. The permittivity of the materials improved significantly as a result of the added carbon nanotubes and their high electrical conductivity. Magnetic properties such as saturated magnetization and coercive force were also improved by the presence of Fe2O3/BaTiO3, which enhanced the permeability. The improved permittivity and permeability significantly contributed to effective shielding of electromagnetic interference measured at 37 dB. (C) 2010 Elsevier B.V. All rights reserved.