The amorphous Ni-Mo film with high HER (hydrogen evolution reaction) activity was obtained by pulse plating. The optimum electrodeposition conditions with respect to HER overpotential were determined, e.g. Na(2)MoO(4)center dot 2H(2)O concentration, current density and duty cycle. Correspondingly, the compositions and components of the Ni-Mo coatings with various molybdenum contents were investigated systematically. The results showed that when the ratio of nickel and molybdenum concentrations in the electrodeposition bath is lower than 1 (mol%), the molybdenum content in the coating decreases with the increasing Na(2)MoO(4)center dot 2H(2)O concentration, while the corresponding HER overpotential of the Ni-Mo film increases. The amorphous Ni-Mo coating was obtained when the molybdenum content was c.a. 30 mass%, which shows high HER activity (eta(200) = 62 mV at 200 mA cm(-2) and 80 degrees C) and excellent corrosion resistance. After galvano-static electrolysis for 100 h in 33 mass% NaOH solution, the amorphous structure was destroyed due to the dissolution of molybdenum. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.