The carbon films prepared from polyimide Kapton were investigated by XPS and elemental analysis. The chemical states of carbon and nitrogen gradually changed with carbonization temperature and the changes in the peak intensity ratio of I[N1s]/I[C1s] by XPS were consistent with N/C mole ratios by elemental analysis. The N1s peak around 401 eV which was a main component at 1200 degrees C was considered to correspond to quaternary species such as a pyrrole type nitrogen. This species may exist in the carbon films prepared at 2000 degrees C and affect their properties. (C) 1997 Elsevier Science Ltd.