A general hydrothermal synthesis technique has been developed for the large-scale preparation of perovskite oxide nanocrystals of BaTiO3 (BT), SrTiO3 (ST) and PbTiO3 (PT). X-ray diffraction pattern (XRD) and Raman spectrum revealed that tetragonal BT was successfully synthesized. The obtained ST and PT were in cubic and tetragonal phase, respectively. Scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM) images showed that all of the products were on nanometer scale. These nanocrystals should provide an ideal candidate for fundamental studies of nanoscale ferroelectricity, piezoelectricity, and paraelectricity. Meanwhile, the synthetic strategy may be easily extended to prepare other nearly monodispersed nanocrystals of perovskite oxides or solid solutions. The relative studies are in progress and will be reported later. (C) 2007 Elsevier Ltd. All rights reserved.