Polymer electrolyte fuel cell performance strongly depends on properties of the stack bipolar plates. Stainless steel, being an attractive material for bipolar plates, raises major concern as having a high contact resistance. It is assumed that most of this contact resistance is governed by electrical properties of the developed oxide surface film. Accurate consideration of existing data and measurements of mechanically treated stainless steel/carbon interface reveals a substantial influence of surface topography on the contact resistance. Contact resistance may change tenfold, depending on substrate surface treatment and roughness. A model describing carbon/stainless steel interface is introduced, explaining the observed behavior. (c) 2006 Elsevier B.V. All rights reserved.