Fuel cells are being developed to provide transportation applications. This paper discusses the clean, efficient propulsion power in promise and problems of the solid oxide fuel cell (SOFC) for the automotive application. The SOFC system requires a simple, compact fuel processor, even for complex fuels such as gasoline and diesel fuel. Because of the similar operating temperatures, the fuel processor and the fuel cell stack can be close-coupled, offering a high degree of thermal integration for a high net power density for the system. Although the startup of the SOFC system would not be new instantaneous, it would not necessarily require more time than for other types of fuel cell systems operating on conventional or alternative transportation fuels. Simulations of system performance show that high efficiencies should be achievable. Developments in advanced interconnect and other cell and stack materials are expected to greatly improve the thermal and mechanical ruggedness of the fuel cell stack. Although the balance of plant is relatively simple, some components still need development, such as an air preheater offering high heat transfer in a small volume.