The temperature increment in electrodes and electrolyte of a fuel cell is mainly attributed to the chemical reaction and the irreversibilities. The aim of this work is to study the increasing temperature of a SOFC single cell under the influence of the electrode and electrolyte thicknesses for its type of heat source. The hydrogen and water field are also discussed according to anode thickness. The results of a self-developed mathematical model show the increasing temperature in the solid side of SOFC; anode, electrolyte and cathode by heat source types "Joule effect" at the several geometric configurations of SOFC. The maximum temperature value is also discussed for several cathode thicknesses under the activation polarization effect. Moreover, mass transfer for both hydrogen and water is studied according to anode thickness. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.