The oxidation phenomena of alumina-supported palladium prepared from various precursors has been investigated by a simultaneous thermogravimetric analysis-differential scanning calorimetric (TGA-DSC) technique over a wide temperature range between 250 and 900 K. Three different temperature ranges were found in oxidation on Pd(C)/Al2O3: chemisorption of dioxygen at 250-300 K; penetration of adsorbed oxide ions into sublayers at temperature over 300 K and formation of a stable bulk oxide at 800 K. However, four different temperature ranges were found on Pd(N)/Al2O3: chemisorption of dioxygen at 250-300 K and further formation of unstable (PdO2)-O-s at 300-320 K; decomposition of (PdO2)-O-s into (PdxO)-O-s at 320-420 K; penetration of adsorbed oxide ions into sublayers at temperature over 420 K; and formation of a stable bulk oxide at 800 K.