There has been measured heat conductivity of PbTe up to 1350° and PbSe up to 1500°K. The investigations were carried out by using the flat layer method and the coaxial cylinders method. The relative error of the measurements did not exceed 10%. The contribution of separate components into the total heat conductivity was determined by calculation. There has been found a considerable deviation from the Wiedemann-Franz law in caseLexpof PbTe melt equals approximately 0.5 Lo(Sommerfeld Lorentz number)