The dependence of the hydrogen evolution reaction (HER) on plastic strain has been studied on polycrystalline pre-strained nickel electrodes in H2SO4 1 M using linear voltametry. A thermodynamic approach is proposed to determine the influence of temperature and plastic strain on HER characteristic parameters as symmetry coefficients, activation enthalpies, number of active sites, on the different steps of the HER mechanism. A direct correlation is established between crystallographic defects associated with dislocations emerging at the surface of nickel electrodes, in terms of density and distribution of defects, and the efficiency of electrochemical processes occurring during HER: hydrogen adsorption and desorption. (c) 2006 Elsevier Ltd. All rights reserved.