In this work, hydrogen absorption in a LaNi5-H-2 reactor is investigated experimentally and numerically. Experimental measurements were carried out on a cylindrical metal-hydride reactor filled with LaNi5 alloy. During the experiments hydrogen was charged at a constant pressure. The performance of the reactor during hydriding process was obtained at different fluid temperatures and hydriding process was identified from measured temperature histories. The temperature changes in the reactor were measured at several locations and recorded in a computer. The numerical simulation of the reactor was also performed. A two-dimensional mathematical model has been established and solved numerically by the method of finite volume for the simulation. The numerical results are compared with the measured data to validate the mathematical model. The predicted results are in good agreement with the experimental measurements. Copyright (c) 2005 John Wiley & Sons, Ltd.