Alloying Zn with Cr increases the corrosion protection of steel at a reduced layer thickness. The cathode current efficiency of Zn-Cr alloy electrodeposition is 50-70%, which reflects the relatively high share of the side reaction of hydrogen evolution. In this regard, the hydrogen permeation process during the electrodeposition of Zn and Zn-Cr coatings on steel was investigated in a conventional Devanathan-Stachurski cell. Two types of base electrolyte compositions and PEG 1500 as an additive were used. For all electrolytes, the hydrogenation of the steel is most intensive in the initial stage of the electrodeposition because of the lower hydrogen overvoltage on steel. The difference in the base composition of the Zn electrolytes (ammonium sulfate + boric acid instead of sodium sulfate), does not significantly affect the hydrogen penetration into the substrate. The effect is more pronounced when Cr(III) is added to the base electrolytes. PEG 1500 in the electrolytes for Zn and Zn-Cr plating strongly increases the hydrogen permeation rate during the deposition process, more expressed in the case of electrolytes containing sodium sulfate. The coatings' formation strongly inhibits the hydrogenation of the steel. A thermal desorption ahalysis (TDA) was used to measure the hydrogen desorption rate and hydrogen, differently bound in the steel/coating system was obtained. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.057212jes] All rights reserved.