The phase stability and phase transition temperature of three nano-oxides Al2O3, TiO2 and Fe2O3 are thermodynamically determined by considering effects of surface energy and internal pressure induced by surface stress on the total Gibbs free energy. The established model corresponds to available experimental and simulation results of Al2O3, TiO2 and Fe2O3 nanocrystals. (C) 2007 Elsevier Ltd. All fights reserved.