Mesoporous modified-red-mud (MRM) was obtained via the modification of as-received red mud (RM) by the acid digestion and alkali reprecipitation approach, which was further employed as the support for preparation of Ni/MRM catalysts by the impregnation method. The textural and structural properties of the MRM and as-prepared Ni/MRM catalysts were fully characterized by X-ray diffraction (XRD), thermogravimetry-differential thermal gravity analysis (TG-DTG), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectra (FT-IR) techniques. The catalytic behavior of the prepared Ni/MRM catalysts for ammonia decomposition was investigated, indicating excellent catalytic activity, comparable to the previously reported metal oxide supported Ni catalysts. This study demonstrates the feasibility of utilizing the waste from the aluminum industry for the decomposition of ammonia to hydrogen. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.