The long term performance of SOFC with nanocomposite Ni-YSZ anode and LSM-YSZ cathode was reported. The SOFC was prepared by infiltrating polymeric precursors of NiO and LSM from anode and cathode sides respectively. The fuel cell showed relatively high initial performance (0.49 Watt/cm2 at 800°C) for the given electrolyte thickness (∼170 μm). Long term stability tests showed that the power density dropped to 0.41 Watt/cm2 in the first 60 hours of operation in short circuit conditions and no further change in the power density was observed. Low electrode polarization resistance was obtained (∼0.080 Ohm.cm2 for combined anode and cathode at 800°C) which showed no significant change with prolonged time. The slight drop in power density was related to the change in ohmic resistance which was attributed to the increase in current collection resistance. The fact that the majority of the resistance was due to the electrolyte resistance (∼80%) suggests that stable SOFCs with high power densities could be achieved with thinner electrolytes. After >100 hours of operation at 800°C in short circuit conditions, the fuel cell was measured at higher temperatures. Power densities were 0.71 Watt/cm2 and 1.0 Watt/cm2 at 900°C and 1000°C, respectively.