In this study, a modeling framework for heat and mass transport is established for a unit monolith type SOFC, with emphasis on quantifying the radiation heat transfer effects. The Schuster-Schwartzchild two-flux approximation is used for treating thermal radiation transport in the optically thin yttria-stabilized-zirconia (YSZ) electrolyte, and the Rosseland radiative thermal conductivity is used to account for radiation effects in the optically thick Ni-YSZ and LSM electrodes. The thermal radiation heat transfer is coupled to the overall energy conservation equations through the divergence of the local radiative flux. Commercially available FLUENT(TM) CFD software was used as a platform for the global thermal-fluid modeling of the SOFC and the radiation models were implemented through the user-defined functions. Results from sample calculations show significant changes in the operating temperatures and parameters of the SOFC with the inclusion of radiation effects. (C) 2003 Elsevier B.V. All rights reserved.