The influence of the size and nature of counter-ions on the permeability of polypyrrole films to hydrogen was tested. The permeabilities were determined using the method of limiting currents on a Pt rotating disc electrode with subsequent Koutecky-Levich analysis. The work has focused mainly on the influence of the anion size, but the effect of polymeric anion hydrophilicity was also considered. Attention was especially paid to Nafion(R) as a counter-ion. It was found that Nafion(R) markedly increases polypyrrole permeability. The film growth was followed by means of EQCN, which allowed determination of the polypyrrole film densities.