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The aim of this work was to find an effective annealing treatment leading to a complete elimination of Te inclusions and simultaneously to conservation of the resistivity of CdTe:Cl crystals with varying chlorine doping level. This goal was reached by an application of two post-growth annealing steps. The first annealing step performed under Cd overpressure led to a significant reduction of Te inclusions. However, Cd-rich thermal treatment converted crystals into high-conductive n-types and re-annealing of the material in a Te atmosphere was necessary to restore the material resistivity. After application of the second annealing step under Te overpressure, resistivity higher than 108 Ωcm was observed only in samples with high chlorine doping levels of nCl ≈ 2 × 1017 cm-3. In addition, a new emission at 1.26 eV was observed in the photoluminescence spectra after two-step annealing. The size of Te inclusions, resistivity, photoluminescence spectra and detection properties of CdTe:Cl crystals before and after the two-step thermal treatment are discussed.