A finite volume model of a solid oxide fuel cell has been developed. The model applies a detailed electrochemical and thermal analysis to a tubular SOFC of given geometry, material properties and assigned input flows. Electrochemical modeling includes an evaluation of ohmic, activation and diffusion losses as well as a kinetic model of hydrocarbon reactions, based on most recent literature experiences. Internal heat exchange coefficients have been calculated with a specific fluid-dynamic finite volume analysis. The model is calibrated on the available experimental data for atmospheric and pressurized tubular SOFCs, showing the capacity of predicting accurately the SOFC operating conditions. The model generates total cell balances and internal cell profiles for any relevant thermodynamic or electrochemical variable, giving the possibility of discussing the effects of different operating conditions on the internal FC behavior. A sensitivity analysis is carried out to investigate the effects of different assumptions on a selection of key model parameters involved in the calculation of cell losses, internal heat exchange process and reforming reactions. Among other results, it is shown that the importance of the adoption of appropriate parameters for the evaluation of activation polarization, as well as the relevance of a kinetic model for reforming reactions. (C) 2004 Elsevier B.V. All rights reserved.