materials with perovskite structure are potential catalysts for preventing greenhouse gas emissions to the environment. several methods have been proposed for the synthesis of these materials in order to produce homogeneous powders with nanometric particle size. in the present work, the la0.8ca0.2mno3 and la0.8ca0.2coo3 systems were prepared by the polymeric precursor method for application in automotive catalysis. this method was chosen because it allows obtaining homogeneous powders and crystalline phases at lower temperatures. the powders were calcined at 700 and 900 oc for 4 h and characterized by thermal analysis, x-ray diffraction and scanning electron microscopy techniques. the perovskites are nanometric, single phased and present suitable properties for use in automotive catalysis.