Zn-Mn electrodeposition from additive-free chloride bath on steel was investigated. Several operating parameters, namely the Mn2 concentration, the current density and the stirring were explored with regard to the Mn content in the Zn matrix. The Mn content depends on the applied current density and jumps from zero to a maximum of 11.4% under 140 mA/cm2. At high current density, Zn-Mn coatings are darker, more dendritic and with bad adhesion to the substrate. The dark appearance of Zn-Mn alloys is linked to oxy/hydroxide inclusions formed into the co-deposits.