The ethanol oxidative steam reforming reaction was studied over a rhodium-based catalyst that was prepared by wet impregnation method. The oxygen-to-ethanol ratio (R-o = 01.2), space time (tau(Et) = 1545 g(cat).min/mol(Et)), and temperature (T = 673873 K) were varied to determine the reaction scheme. The catalyst showed excellent selectivity for the production of hydrogen and a very good stability. A network of eight reactions was used: ethanol decomposition and steam reforming; water gas shift; methane steam reforming; and ethanol, methane, carbon monoxide, and hydrogen oxidations. The obtained results suggest that the oxidation reactions predominate in the first part of the reactor and at low temperatures. Ethanol partial oxidation was also studied, and the same reaction scheme was found for this reaction when varying R-o (0.251.0), tau(Et)(9.545.8 gcat.min/molEt) and T (573673 K). Finally, a reaction mechanism of 22 elementary steps was proposed, and the kinetic parameters were obtained.