Three-dimensional (3D) hydrogen evolution reaction (HER) catalysts are admirable for their advantages of enhanced electrolyte diffusion, more efficient utilization of active sites and easy release of hydrogen bubbles. In this work, the binder-free 3D cathode CoMoSx/CC has been successfully fabricated with the employment of 3D electrode, carbon cloth (CC). CoMoSx film was successfully deposited on CC with controllable morphology and thickness by the convenient co-electrodeposition process. Moreover, the deposition conditions have been optimized systematically. CoMoSx/CC fabricated under optimum conditions has achieved excellent HER performance with a small onset overpotential of 100 mV. It needed only 100, 125 and 180 mV overpotential (vs. RHE) to reach the current density of 10, 20 and 100 mA/cm(2) respectively, which performed the highest electrocatalytic activity among binary metal sulfide HER catalysts ever reported. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.