Solid oxide fuel cells (SOFC) are a promising technology for distributed electricity generation and cogeneration. Numerous papers have been published in the past several years proposing mathematical/computational fluid dynamics (CFD) models for predicting the transient and steady-state performance of such cells. In this paper, a detailed steady-state CFD model of a planar anode supported SOFC is proposed, which accounts for mass, thermal, and charge transport as well as electrochemistry and the chemistry of internal fuel reforming. Its main characteristics include the use of a continuous model for the electrochemistry, allowing one to examine different three-phase boundary geometries. This is an improvement over the typical model reported in literature, which utilizes an equivalent resistive circuit approach or a homogeneous distribution of three-phase boundaries. The model proposed here is used to simulate the degradation of anode, cathode, and electrolyte due to instabilities (e.g., anode oxidation due to fuel depletion) or to the delamination of the electrodes from the electrolyte. Such degradations result in a drop in cell performance but are difficult to predict without the use of models that can be helpful for diagnosis. The model is applied to experimental data available in literature both for the nondegraded and degraded cases.