A dynamic model for a single, spatially distributed molten carbonate fuel cell (MCFC) in cross-flow configuration is presented. The equations are formulated in dimensionless terms and are based on balances of mass, enthalpy, and charge. They include a detailed description of the electric potential field, reforming reactions inside the anode channel, mass transport resistance between the bulk gas phase and the electrochemical reaction zone inside the electrode pores, a catalytic combustion chamber, and the recycling of cathode exhaust gas. The simulation yields transient and spatially distributed profiles of temperatures, concentrations, gas fluxes, and current density as well as the cell voltage and the electric power over the full range of operating conditions. It is therefore a useful basis for system design, optimization, and control design of MCFC, applicable to any size of MCFC and transferable to other high-temperature fuel cells such as the solid oxide fuel cell. The complete set of model equations is presented in detail. Some exemplary steady state and transient simulation results are presented and compared to results from other models. (c) 2005 The Electrochemical Society.