Cerium-doped yttrium aluminum garnet (YAG:Ce3+) powder phosphor is synthesized via spray pyrolysis of polymeric precursor solution obtained by dissolving the corresponding nitrates in ethylenediaminetetraacetic acid (EDTA). Ultrasonically generated aerosol droplets are decomposed at 600°C in argon atmosphere. Following the initial attempt in providing pure YAG:Ce3+ phase generation the particles were additionally thermally treated for 3h in air at 1000 and 1100°C. The powder morphology is followed with scanning electron microscopy (SEM), while inner particle structure is analysed by analytical and high-resolution transmission electron microscopy (TEM). Phase identification is performed by X-ray powder diffraction (XRPD) based on which a structural refinement through Rietveld method was done. The spherical submicronic particles have grained sub-structure comprising clustered garnet monocrystals sized below 100nm. The YAG:Ce3+ emission shows wide peak in the range 470–600nm with the maximum near 520nm.