In this work, the simultaneous electrodeposition of nickel with zinc was studied in order to determine the influence of the composition of the deposition solution on the properties of the obtained electrodeposits. It was founded that the Ni/Zn concentrations ratio in solution determines the deposition mechanism and thus, the chemical composition and the electrochemical activity of the electrodeposited alloys; in our studied conditions, contrariously to the typical results from these acidic chloride media, Ni-rich alloys (%Ni > 90) were formed by a normal codeposition mechanism with a better electrochemical activity than Ni for the hydrogen evolution reaction HER reaction. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3567029] All rights reserved.