The behavior of CdTe is well studied at room and lower temperatures. But at T>400 K mainly the measurements under Cd vapor pressure were performed. The quantity of publications of high temperature Hall effect measurements in Te-saturated atmosphere is small. It can be explained by the great aggressiveness of Te vapor. Therefore the lack of necessary information causes the great number of suppositions about dominating defects and their existence area. The purpose of this work was to investigate undoped CdTe single crystal electrical properties in Te-saturated atmosphere in 400-1100 K temperature range. CdTe single crystals were grown by Bridgman method. High temperature Hall effect measurements under well-defined Te vapor pressure were carried out. Point defect structure modeling was calculated using our set of quasichemical defect reaction constants [1]. The results of high temperature Hall effect measurements in undoped CdTe under Te saturated atmosphere showed p-type conductivity up to ∼ 720 K. Then conductivity of intrinsic type was observed. And only starting at T > ∼970 K electron conductivity began to prevail. This fact can be explained by foreign point defect influence, since the hole conductivity didn’t depend on Te vapor pressure. The charge carriers concentration in Fig. 1 was calculated using the classical formula. But in intrinsic conductivity area its usage was not valid. So using equations for bipolar conductivity we determined the concentrations of donors and acceptors separately (Fig. 2). It is seen that electron type conductivity at T>970 K was caused by intrinsic electrons, because their slope in temperature dependency was ∼1.6 eV. The slope of holes was equal 0.2 eV. The nature of possible acceptors is unclear now. Since hole density is high (up to 1017 cm-3) one can suppose that oxygen is responsible for observed results.figureFig. 1. Temperature dependence of 1/eRH in undoped CdTe at Te saturation.figureFig. 2. Temperature dependence of carrier concentration in undoped CdTe at Te saturation.