A model of a ATR fixed bed reactor with Rh catalyst has been developed and validated on the basis of experimental results. Experiments have been conducted in a small scale reactor and solid temperature profiles have been measured with IR camera. Temperature profiles present high peak temperature at reactor entrance as consequence of the partial separation in space of the reforming and oxidation reactions. Thus, the kinetic model for Rh catalyst refers to an indirect scheme including a shift factor which is crucial for good predictive capabilities of the reactor model. The model validation has been conducted by comparing solid temperature profiles with those obtained experimentally at different feed compositions, total flow rate and preheating temperatures. The model well describes the experimental results in all the investigated operating conditions. The validated model has been then used to analyze the effect of thermal conductivity and of the flow rate on overall reactor performances. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.