In the present work temperature dependence of heat capacity of cesium tantalum tungsten oxide has been measured first in the range from 7 to 350 K and then between 330 and 630 K, respectively, by precision adiabatic vacuum and dynamic calorimetry. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity C-p degrees (T), enthalpy H degrees (T) -H degrees (0), entropy S degrees (T) - S degrees (0) and Gibbs function G degrees (T) - H degrees (0), for the range from T -> 0 to 630 K. The structure of CsTaWO6 is refined by the Rietveld method: space group Fd3m, Z= 8, a=10.3793(2) angstrom, V= 1118.14(4) angstrom(3). The high-temperature X-ray diffraction was used for the determination of temperature of phase transition and coefficient of thermal expansion. (c) 2008 Published by Elsevier B.V.