With same procedure and same starting materials, nearly monodispersed alpha-Fe2O3, gamma-Fe2O3 and Fe3O4 nanoparticles were synthesized on an large scale of about 60 g in a single reaction through a low temperature sol-gel route. The simple preparation process includes the reactions between FeCl2 and propylene oxide in ethanol solution at boiling point to form a sol and the following drying of the sol. The different iron oxide phases can be obtained just by changing of the drying conditions for the sol solution. The strategy developed in this study offers important advantages over the conventional routes for the synthesis of alpha-Fe2O3, gamma-Fe2O3 and Fe3O4 nanoparticles, showing potential for its application in industrial production of iron oxides. (C) 2012 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.