The flat temperature wave method was used to measure the thermal diffusivity and heat capacity of cubic carbides of zirconium and niobium at high temperatures in the region of homogeneity. The energies of formation of equilibrium thermal vacancies were determined. The electrical resistance of the same samples was measured by the usual potentiometric method. Using the data obtained, the thermal conductivities of the samples and their electron components are calculated. The results obtained are discussed.