The effective thermal conductivity (ke) of a MmNi 4.5Al0.5 hydride powder bed was measured using an one-dimensional steady-state axial heat transfer comparative method. The experiments showed that ke lies between 0.1 and 1.2 W/m K in the pressure and the temperature ranges of 0-50 bar and 0-100 °C, respectively. While hydrogen pressure and concentration showed strong influence on k e over the complete range, the temperature effects were minimal. Thermal conductivity of the solid materials, MmNi4.5Al0.5 alloy and its hydrides, was also back calculated from the experimentally measured ke values. © 2011 American Chemical Society.