In the present work temperature dependence of heat capacity of cesium tantalum tungsten oxide has been measured first in the range from 7 to 350K and then between 330 and 630K, respectively, by precision adiabatic vacuum and dynamic calorimetry. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity C p ° (T), enthalpy H°(T)− H°(0), entropy S°(T)− S°(0) and Gibbs function G°(T)− H°(0), for the range from T →0 to 630K. The structure of CsTaWO6 is refined by the Rietveld method: space group F d3m, Z =8, a =10.3793(2)Å, V =1118.14(4)Å3. The high-temperature X-ray diffraction was used for the determination of temperature of phase transition and coefficient of thermal expansion.