A polycrystalline sample of a new triple molybdate AgMg3Ga(MoO4)5 was obtained by solid-state reaction techniques. Structural refinement based on X-ray powder diffraction data showed that the crystal structure is isotypic with NaMg3In(MoO4)5 (sp. gr. P
). In the structure pairs of edge-shared (Mg, Ga)O6, octahedra are connected by common vertices to form a three-dimensional framework. Large framework cavities involve Ag+ cations. The title compound was found to melt at 1079 K.