X-ray diffraction and calorimetric investigations were performed for 80GeS(2)-20Ga(2)S(3), 82GeS(2)-18Ga(2)S(3)and 84GeS(2)-16Ga(2)S(3)chalcogenide glasses. It is shown that structure of these glasses is characterized by short range ordering. It is established that Ga(2)S(3)and GeS(2)phases can be crystallized in Ge-Ga-S system. Transformation of voids in crystallized (80GeS(2)-20Ga(2)S(3))(100-& x445;)(CsCl)(x),x = 0; 5; 10; 15 chalcogenide glasses was studied by positron annihilation lifetime spectroscopy. The CsCl content in GeS2-Ga(2)S(3)glassy matrix changed the defect-related component in positron lifetime spectra and confirmed the structural void agglomeration in comparison with the base glass. A larger amount of CsCl in (80GeS(2)-20Ga(2)S(3))(85)(CsCl)(15)glass resulted in void fragmentation due to loosening of the structure.