A key question relating to the application of solid oxide fuel cells (SOFCs) is the size of the smallest device which can be usefully operated. Previous studies have suggested that 1 kW(e) is the smallest power output that is reasonably attainable, with most applications in the larger power range around 200 kW(e). In this paper we demonstrate that smaller SOFCs can be built, with possible applications to microelectronics and communications al remote sites where gas is available but batteries are expensive. Experiments are described on a three-cell device powered by butane. This was warmed up in minutes at a flow rate of 80 ml/min of butane to give an electrical output between 0.1 and 1 W. The cells were made of zirconium oxide extruded in thin-wailed tube form, with nickel cermet anodes and lanthanum strontium manganite cathodes.