Rapid start-up times are a big challenge for high-temperature fuel cells such as solid oxide fuel cells (SOFCs), especially large-sized stacks with high power outputs. This paper presents the development of tubular and microtubular anode-supported SOFCs and the design and testing of the thermal stability of such single cells and stacks. It was demonstrated that single cells with various sizes have very good thermal shock resistance. Preliminary results also showed that stacks can be started up within minutes and withstand more than 50 thermal cycles and that single cells can withstand temperature changes of 550°C/min550°C/min . Several factors that affect the thermal stability are discussed.