A polypyrrole (Ppy) film has been deposited on a Ni electrode by anodic polymerisation from acetonitrile solutions. X-ray photoelectron spectroscopy (XPS) analysis shows nickel Ni2+ chemically bound to the polymer chain. Impedance spectroscopy has been employed to characterise this new material in a system of metal/film/electrolyte in a Frequency range 10(5)/10(-2) nz. The ac response of the film consists of four or three separable elements depending on the film's thickness. Incorporation of nickel ions into electronically conducting polymer causes, (i) negligible changes ill a polymer redox resistance (high frequency response): (ii) considerable decrease of conductivity responding to ac signal at medium Frequency; (iii) linear dependence between resistance measured at medium frequency of ac signal and electrode potential appeared to be caused by nickel presence in the film. Effective diffusion coefficient established fur Ppy layers on Ni, Pt and stainless steel at OCV potentials are 1.2 x 10(-10), 1.0 x 10(-8), and 1.2 x 10(-9) cm(2) s(-1), respectively.