The composition, surface morphology and appearance of Zn-Co alloy deposits as a function of current density, electrode potential and Co2+ concentration in the electrolyte was studied. It was found that coatings of good quality with low (1%) Co content are formed at a current density of 0.2 A dm(-2) and with high (6.5%) Co content at 2 A dm(-2) from electrolytes containing 1.0 M Co2+ under galvanostatic conditions. The potentiodynamic dissolution of coatings with Co content of 6.5% indicates successive deposition of Co enriched phases and a pure Zn phase. The Zn-Co alloys are more corrosion resistant than zinc but are less resistant than cobalt.