It is fundamentally important to determine the deoxidisation and phase compositions of plasma sprayed TiO2 coatings containing anatase. In the present study, plasma sprayed porous TiO2 coatings containing anatase were prepared using anatase powder and both Ar-He-H-2 and Ar-He-N-2 plasma gases. The deoxidisation of TiO2 and phase compositions of the starting powder and the prepared coatings were examined using X-ray Rietveld method by refining their crystalline parameters and scale factors. The refined oxygen occupancies showed that there were about 0.08 and 0.1 formula units of oxygen deficiencies for the rutile and anatase phases of the coatings, respectively. Such degrees of deoxidisation and the other crystalline parameters appeared independent of the plasma spraying process parameters. With considerations of the presence of organic adhesive in the starting powder and the formation of titanium ethoxide in the coatings, the degrees of deoxidisation estimated by the X-ray Rietveld method were slightly higher than those quantified by the thermogravimetry curves. The phases of the coatings determined from the refined scale factors were mainly composed of rutile with 10.0% to 22.5% anatase by weight, and the latter content increased with decreasing the intensity of the plasma jet. (C) 2004 Elsevier B.V. All rights reserved.