The effects of Cd, Fe and Cu impurities on zinc electrowinning from sulphate electrolyte were investigated by means of polarization curves and cyclic voltammetry. The morphology and the structure of the deposits obtained by small-scale electrolysis were determined by SEM and X-ray diffraction analysis and their purity was determined with an energy dispersive X-ray analyzer. The results indicate that the metallic impurities influence the zinc electrodeposition process, exerting a deleterious effect, by influencing the purity and the morphology of the cathodic deposit. Cd and Cu are co-deposited with zinc on the aluminium cathode and facilitate zinc deposition, while Fe inhibits zinc deposition and does not induce significant changes in deposit morphology.