It has been found that films of polymethylmethacrylate (PMMA) show a substantial conductance after bombardment by Ar ions with energy of 250-1250 eV. The appearance of the conductance is attributed to graphitization processes in the subsurface layer. As the energy of ions increases, the conductivity of PMMA is greatly enhanced. We have found that, at low electric fields, the conductance is provided by variable range hopping with a strong influence of Coulomb interactions. At high electric fields, the transformed PMMA reveals non-Ohmic behavior: the conductance is an exponential function of root EIT. (c) 2005 American Vacuum Society.