The physical-chemical character of chemical phase interaction in the In₂Те₃–Cd_0.9Zn_0.1Те system has been studied by the methods of differential-thermal, X-ray diffraction, microstructure analysis and by microhardness and density measurements. The state diagram of this system has been plotted. It has been established that this system is quasybinary, the state diagram is of eutectical type with monotectic returning. At room temperature the In₂Te₃ solubility extends to 3.5 mol% and solid solution based Cd_0.9Zn_0.1Те is dissolved to 5 mol.%