A silver electrodeposition study has been carried out using C and Pt microelectrodes of radius 5 mum. The special characteristics of the microelectrodes have allowed this study to be carried out in experimental conditions that would be not possible with larger electrodes. For example, electrochemical measurements have been performed without supporting electrolyte. Furthermore, the small number of nuclei formed on these microelectrodes allow a better understanding of the nucleation and growth process. Under certain experimental conditions, step increases in current have been observed in potentiostatic and voltammetric measurements and related to the deposition mode. The importance of the substrate superficial state for nucleation and growth has been clearly shown.