Development of high-performance non-precious metal electrocatalysts for hydrogen production from water splitting in acidic media is attracting more and more interests. We describe here a two-step electrochemical method to prepare Ni-Mo coated coral-like Cu micro-arrays: (i) treatment of a smooth Cu substrate with square wave potential pulses and (ii) induced co-deposition of Ni-Mo coatings. The prepared electrode demonstrates high electrocatalytic activity close to a Pt electrode for hydrogen evolution reactions (HERs) in an acidic medium. The stability of the prepared electrode in the acidic medium is assessed by continuous cyclic voltammetry (CV) and by chronoamperometry. The enhanced electrocatalytic activity of this electrode is attributed to the high surface area and the synergistic interaction between Ni and Mo. The electrode of Ni-Mo coated coral-like Cu micro-arrays is a promising candidate of electrocatalysts for HERs in acidic media. (C) 2016 The Electrochemical Society. All rights reserved.