The capabilities of Electrochemical Impedance Spectroscopy (EIS) to give information on the elementary processes involved in metal deposition are reviewed. In addition to the presence of a multi-step charge transfer, EIS can give evidence of the inhibition of charge transfer by adsorbates (hydrogen, anions, additive molecules) or by an interfacial layer. EIS is also able to provide data connected with the growth mode of electrodeposits and give access to the life-time of active edges. Various examples (Cu, Ag, Ni, Zn) illustrate these situations. For Cu-Ni alloys deposition, EIS points out of diffusion control, the multi-step discharge of ionic species and a particular reactivity of some sites for the nickel discharge.