The effect of hydrogen absorption on the electrical resistance and activation energy of MmNi(4.5)Al(0.5) thin film was investigated. The samples were prepared by oblique deposition at different angles (theta = 130 degrees, 45 degrees, 60 degrees, and 75 degrees) simultaneously at a pressure of 10(-5) Torr at room temperature and thickness of thin film were measured using quartz crystal thickness monitor. It was found that the resistance and activation energy of MmNi(4.5)Al(0.5) thin films increases with the angle of deposition. The activation energy of MmNi(4.5)Al(0.5)H(x) films is found to be higher than MmNi(4.5)Al(0.5) films for the same deposition angle and also increases with angle of deposition. The activation energy of hydrogenated samples in lower temperature range is found to increase with hydrogen charging cycle but in higher temperature range activation energy of hydrogenated samples is found to decrease due to discharge of hydrogen. (C) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.