Cobalt and Cobalt-Nickel alloy thin films were electrodeposited on polycrystalline copper substrates. Electrochemical investigation was focused on the initial stage of electrodeposition by pulsed current in terms of electrode potential. Changes in the immersion potential, E_imm, and the deposition potential, E_dep, were obtained for each rum of pulsed current. This electrochemical behavior of electrode surface proves to be related to alloy elements, surface topograph, and magnetic properties of deposit of several atomic layers.