The catalytic hydrogenation of nitrobenzene using a commercial nickel catalyst supported on silica was studied in a three-phase batch laboratory scale stirred tank reactor. Reaction mixture samples were analyzed by gas chromatography. The aim of the work consists in obtaining a fully functional and practical mathematical model of the reaction kinetics that is easy to implement and able to describe the reaction progression in a wide range of conditions. The effects of temperature, pressure and nitrobenzene concentration for a given catalyst concentration were studied. The model that was obtained is able to describe all the experiments with just one set of parameters and helped to describe and explain phenomena that were observed in an industrial system; the results obtained indicated the possibility of the catalyst surface changing with time by contact with the reaction mixture. (C) 2007 Elsevier B.V. All rights reserved.