Potentiostatic measurements are reported for the growth of silver centres in the absence and in the presence of mixed reduction/oxidation of hydrogen peroxide on carbon microdisc electrodes. The application of growth laws and polarization effects are discussed and it is shown that the silver growth process is kinetically controlled at very short times, becoming diffusion controlled as time increases. From the polarization curves, the rate constants of silver deposition were determined. For the system silver/hydrogen peroxide the results show that the reduction/oxidation of H2O2 at silver substrates is controlled by the occurrence of a non-electrochemical reaction.