In this work, the stability of Pt-Ni and Ru-Ni catalysts supported on a CeO₂-SiO₂ oxide was investigated for oxidative steam reforming of ethanol in a fluidized bed reactor at 500°C, H₂O/C₂H₅OH ratio of 4 and O₂/C₂H₅OH of 0.5. The time-on-stream behaviour of the catalysts was studied for 25 hours at 500°C; very stressful conditions were selected in terms of contact time (50 ms), which was considerably lower than the values commonly selected for ethanol reforming. As expected, due to the high space velocity selected, all the catalysts underwent deactivation with time-on-stream and a decreasing trend in ethanol conversion was observed. The highest activity was obtained over the 2Pt10Ni sample, which reached 95% of ethanol conversion after 25 hours of time-on-stream. The worst results in terms of ethanol conversion and hydrogen yield were obtained over the low-loaded samples: despite the 0.5Ru10Ni and 0.5Pt10Ni catalysts assured high activity in the interval 300-600°C, as previously reported, the small noble metal content resulted in poor stability. The most stable sample was also tested under a real bioethanol stream, containing methanol, sulphur compounds and higher saturated alcohols. Despite the more pronounced extent of deactivation compared to the tests carried out under the pure water/ethanol mixture, the 2Pt10Ni catalyst reached a steady state condition after almost 30 h, with no more activity loss. In fact, the net rate of carbon deposition became equal to zero and the change in coke accumulation was negligible.