Interaction of a non-stoichiometric copper sulphide (Cu2-xS) coating chemically formed on glassy carbon with Ag+ ions as well as the electrochemical behaviour of the coating obtained were investigated in 0.1 M NaOH and 0.05 M H2SO4 solutions by using cyclic voltammetry and X-ray photoelectron spectroscopy (XPS). It was determined that Ag+ ions substitute the components of the Cu2-xS coating such as Cu+, Cu2+ and S-0 which may amount to 40 at.%. About 50% of Ag-0 and Ag2O was detected in the coating modified by Ag+ ions. It is believed that Ag-0 is formed in two ways, viz. in the course of oxidation of Cu+ and S-0 : Cu2S + 4Ag(+) --> 2Ag(0) + Ag2S + 2Cu(2+), 4Ag(+) + S-0 + 3H(2)O --> 4Ag(0) + H2SO3 + 4H(+). Finely dispersed S-0 present in the Cu2-xS coating and freshly prepared finely dispersed Ag-0 may interact according to the reaction 2Ag(0) + S-0 --> Ag2S. The coating modified by silver ions, may be electrochemically copper plated in any electrolyte.