Electrically conducting Poly(carbonate) (PC)/poly(pyrrole) (PPy) composite films were synthesized by exposing PC films containing ferric chloride as an oxidant to pyrrole vapour under various polymerization conditions. and their electrical conductivity and morphology were studied. After pyrrole was polymerized in PC matrix for two hours, the composite films showed the conductivity as high as 10-4~10-3S/cm and it increased with the concentration of the oxidant and the polymerization time and decreased with the polymerization temperature. Threshold conductivity was observed when the content of PPy in PC/PPy composite film was ca. 4.5~5 weight percent. The formation of PPy in PC matrix was confirmed by FT-IR spectra anal scanning electron micro-graphs. The x-ray diffraction curves indicated that talc structure or Pc/PPy composite film was amorphous. The conductivity increased one order of magnitude by mechanical stretching.