Nanoparticles of La0.8Sr0.2Co0.8Fe 0.2O3, which are being investigated as cathode materials for intermediate-low temperature solid oxide fuel cells, were successfully synthesized by a novel sol-gel process. The thermal decomposition behavior of gel precursor was examined using TG/DTA analysis. Development of crystalline phases in the powders calcined at various temperatures was monitored by x-ray diffraction. Single phase La0.8Sr0.2Co 0.8Fe0.2O3 could be obtained after calcining at 800°C. A small amount of impurity phase existed in the powders calcined at the temperature below 700°C. Morphological analysis of the powders calcined at various temperatures was done by scanning electron microscopy. The synthesized powders had an average particle size of 30∼90nm at 600-1100°C. The average particle size of the powders increased with increase in calcination temperature. Noticeable changes occurred at temperature above 800°C, and the coarse particles existed in the powders calcined at high temperatures.