Thermodynamic analysis for system ZnO:Cl is performed by means of Kroger method of quasi-chemical reactions. We obtained equilibrium concentrations of defects and free carriers as a function of partial pressure of components in gas phase. When Chlorine total concentration of incorporated Chlorine is 1020 cm(-3) expected concentration of carriers generated is about 5 1019 cm(-3), which is almost three orders of magnitude higher than the one of pure ZnO. (c) 2007 Elsevier B.V. All rights reserved.