Carbon fabrics (CFs) coated with 5.0, 15.0 and 30.0 wt% polyaniline (PANI) (PANI-CFs) have been synthesized by soaking CFs in a 1.0 wt% PANI formic acid solution. The real permittivity (epsilon') of the PANI-CFs was increased with increasing PANI loading, while the imaginary permittivity (epsilon '') was decreased. The resistivity of the PANI-CFs decreased with increasing temperature in both the vertical and diagonal directions. The conductivity increased more obviously with increasing PANI loading along the diagonal direction than the vertical direction, indicating that PANI has improved the conductivity more significantly in the diagonal direction. The maximum negative magnetoresistance of -7.5% and -3.5% was detected for the PANI-CFs with 30 wt% PANI loading in the vertical and diagonal directions, respectively.