In this paper, effect of input voltage to the electrodes on hydrogen production rate (HPR) and efficiency (eta) of hydrogen production was studied. The input DC voltage to the cell was maintained at 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 3.0, 6.0, 9.0 and 12.0V. The optimum input voltage was found between 2.0 and 2.4V for the best efficiency. The extra-over potential voltage to the electrodes would be the cause of energy loss through heat. Sensitivity analysis of the system for voltage with respect to HPR has been carried out and the results are also presented in the paper. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.