The decomposition of Rh2O3 thin films (1 - 10 monolayers) for Rh(100) and polycrystalline rhodium at 400 - 1600 K is studied by thermodesorption (TD) and mathematical modeling. The decomposition of oxide films is accompanied by O-2 liberation at 800 - 900 K and by the appearance of the corresponding ''narrow'' beta(1) peak in the TD spectrum. The model of decomposition, in which the surface layer of the oxide film is continuously covered and its thickness gradually decreases, is considered.