Cyclic voltammetry technique was used to compare the mechanism of the deposition of In, Co and Co-In from citrate electrolytes. Samples of Co-In coatings were electrodeposited at different current densities to permit the subsequent investigation of their physicochemical characteristics. It was established a strong relation between Co-In phase composition and the electrolysis conditions. At low current densities below the limiting current only In was deposited. At higher current the alloy phase of CoIn₃ was formed, besides that of In, and minority phases were Co and Co(OH)₂. At higher current densities of about 0.8-1.5 A/dm², when intensive hydrogen evolution was observed, specific patterns (spirals, waves, targets) were visible onto the Co-In coating surfaces, considered as spatio-temporal structures. The pattern formation could be promoted by the specific hydrodynamic conditions close to the cathode-electrolyte interface and by the concentration fluctuation of the ionic species.