[en] Phase equilibria in the MgMoO₄-Ln₂(MoO₄)₃ systems (Ln=La, Gd) have been studied by static and dynamic methods of the physico-chemical analysis, using differential thermal, visual-polythermal, crystal-optical, X-ray phase, and infrared spectroscopic methods, and their phase diagrams have been constructed. Phase equilibria in the systems studied are characterized by limited solubility of components in the liquid state, formation of solid solutions on the base of α- and β-forms of Gd₂(MoO₄)₃. Eutectics in the MgMoO₄-Ln₂(MoO₄)₃ (Ln=La, Gd) systems corresponds to the composition of 71 mode % La₂(MoO₄)₃-29 mole % MgMoO₄, tsub(melt)--935+-5 deg C and 57 mole % Gd₂(MoO₄)₃-43 mole % MgMoO₄, tsub(melt)=1020+-5 deg C. The region of glass formation has been established