In the present work, we explored the possibility of obtaining nanocrystalline powders of lanthanide-doped Y3Al5O12 (YAG, yttrium aluminum garnet) using solution propellant synthesis, a novel technique that has been proven to be capable of producing nanopowders of numerous oxides at relatively low temperatures and in a rapid way. A series of YAG samples containing a number of different trivalent lanthanide ions (Eu, Er, Ho, Tm) was produced. Samples were characterized by X-ray diffraction for phase identification and line broadening analysis, and by electron microscopy (SEM and HRTEM) for morphological and nanostructural investigation. The samples have a polycrystalline porous structure made up of particles in the nanometer range. Crystallites have a high degree of disorder; the ones doped with Eu3+ are characterized by an intense and well-resolved luminescence spectrum in the visible region.