Internally reforming anode supported solid-oxide fuel cells (SOFC) running on humidified CH4 is studied numerically. The computational framework employs detailed multi-step models for heterogeneous chemistry for Ni catalysts. The electrochemistry is implemented using a modified Butler-Volmer setting based on elementary charge transfer kinetics. Transport through the porous matrix is modeled using the dusty gas model (DGM). Parameters required for the electrochemical model are adjusted to reproduce experimentally observed data. Obtained parameters are then used to model a co-flow planar single cell under internally reforming conditions assuming the interconnect walls as adiabatic. Numerous runs with varying inlet conditions of cathode stream are carried out to deduce the behavior of temperature and current density distribution in the cell. Results show that internal reforming generally leads to a temperature drop near the inlet boundary. © 2007 Elsevier Ltd. All rights reserved.