Nano-sized TiO2 particles are of interest for many applications, including use as photocatalysts and in heat transfer fluids (nanofluids). In the present study, TiO2 nanoparticles with controllable phase and particle size have been obtained through homogeneous gas-phase nucleation using chemical vapor condensation (CVC). The phase and particle size of TiO2 nanoparticles under various processing conditions have been characterized using x-ray diffraction and transmission electron microscopy. Chamber temperature and pressure were found to be two key parameters affecting particle phase and size. Pure anatase phase was observed for synthesis temperatures as low as 600 °C with chamber pressure varying from 20-50 Torr. When the furnace temperature was increased to 1000 °C at a pressure of 50 Torr, a mixture of anatase and rutile phases was observed, with the predominant phase being anatase. The average particle size under all the experimental conditions was observed to be less than 20 nm.