Amorphous poly‐ether‐ether‐ketone (PEEK) films have been implanted with a variety of ions (He, N, F, As, Xe and I) in the energy range 50 keV to 32 MeV. At the lower end of this range, the dependence of the electrical conductivity of the PEEK on the dose and ion species has been explained in terms of a simple model of electronic and nuclear excitation effects. Implantations in the MeV energy range yielded a surface layer on the PEEK with a high conductivity [up to 2.5 (&OHgr; cm)−1] and a moderate hardness (320 knoop, 1‐g load). Evidence for diffusion of iodine implanted at the highest energy has been found. The role of the uniform iodine concentration throughout the implanted layer in the prevalent conduction mechanism is not known at present.