Electromagnetic interference behaviour of conducting polyaniline composites in the radio frequency range X, Ku, and Ka bands is presented. Methods for determining the conductivity and the shielding effectiveness are discussed. The conducting composites are made from CSA-doped polyaniline blended with the styrene acrylonitrile host polymer. The samples exhibit high conductivities, up to 104 S.m−1, and therefore are compatible with an electromagnetic shielding application. The percolation threshold is very low—below 1% of mass fraction of polyaniline in the blend—and the shielding effectiveness is up to 70 dB, depending on the sample.