Olive mill wastewater (OMW) is a pollutant effluent of the olive oil production. To reduce the environmental impact of this agro-industrial sector, with simultaneous valorization of such waste, the steam reforming of OMW was studied in this work. Besides the reduction of pollution resulting from OMW, the process allows producing "green" H-2. In this study, several commercial catalysts (Ni-, Cu-Zn- and noble metal-based) were tested to compare their performances. A catalytic screening study with all the commercial catalysts was performed, and stability tests were conducted with the material that demonstrated higher activity (Rh-based catalyst). The physicochemical characterization of the fresh and spent materials was realized through several techniques (temperature-programmed reduction, temperature-programmed oxidation, transmission electron microscopy, temperature-programmed desorption of CO2, temperature-programmed desorption of NH3, chemisorption of H-2, scanning electron microscopy with energy dispersive spectroscopy and physical adsorption of N-2 at -196 degrees C). Although there are some materials with good catalytic performance, the Rh-based sample stood out during the tests, exhibiting high catalytic activity and high stability: at 400 degrees C the H-2 yield (over 9 mol(H2).mol(OMW)(-1)) and total organic carbon (TOC) conversion (>98%) were high along all the 24 h of the stability test. (C) 2021 Elsevier Ltd. All rights reserved.