The glass-forming region in the Se-Ge-Zn (I) and GeSe3-ZnSe-Ag2Se [II] systems are determined, as well as some physical and chemical properties (temperatures of softening, crystallization a nd melting, density and microhardness). The glass-forming region in system I on the Se-Ge side (concentration limits 0-43% Gel. The maximum solubility of Zn is around 6% (at Se:Ge = 9:1). The glass-forming region in system [I lies on the side Ag2Se-GeSe3 (from 54 to 100% GeSe) and ZnSe-GeSe3 (from 78 to 100% GeSe3) of the Gibbs’ concentration triangle for GeSe3-ZnSe-Ag2Se.