Highly electrically conducting fabrics were prepared by chemical polymerization of poly( 3,4- ethylenedioxythiophene) ( PEDOT) on a PET fabric. Monomer solution was prepared by dissolving EDOT and poly( vinyl pyrrolidone) ( PVP) as a binder in 1- butanol. The oxidant solution was prepared by dissolving ferric p- toluene sulfonate ( FTS) in 1- butanol. The mixture of the monomer and oxidant solutions was applied to PET fabric and polymerization was carried out under various conditions. We studied the effect of the chemical polymerization conditions on the properties of resulting composites such as electrical conductivity and surface morphology, environmental stability, electromagnetic interference shielding effectiveness ( EMI SE). The specific volume resistivity, specific surface resistivity and EMI SE of the resulting composite were extremely low as 0.15 Omega.cm, 10 Omega/square and quite high as 18 dB, respectively.