Electrochemical techniques (cyclic and linear sweep voltammetry) at rotating and stationary pyrite electrodes were used to study the interaction of pyrite with silver ions in nitrate supporting electrolyte, pH 3 and room temperature. At potentials just negative of the open circuit potential of pyrite, metallic silver was deposited by a nucleation-growth mechanism. Evidence for a surface ion exchange involving removal of Fe2+ from pyrite and replacement with silver ion was found (i) from an analysis of peak potentials for voltammograms taken after various immersion times and (ii) from the appearance of a peak at potentials negative to that for deposition of silver.