This work analyzes different models to describe internal methane reforming in solid oxide fuel cells (SOFCs). Two approaches have been generally used for it: equilibrium and kinetics. In the first case-equilibrium-methane reforming is considered to be fast enough to reach equilibrium. Contrarily, kinetics-based theories assume that the reforming reaction is very slow and does not reach equilibrium. in this case, a reforming rate equation is needed. Four cases are considered: one equilibrium model, two kinetics models and a mixed model. Results show that methane reforming does not follow a unique pattern along the anodic duct and a local detailed analysis is demanded. Furthermore, a mixed model must be used for multidimensional SOFC modelling, although equilibrium is globally satisfactory and, therefore, it is appropriate for 0-D models. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.