Sub-micronic particles are of considerable interest for a wide variety of applications, such as catalyst or optical ceramics, due to their unique properties determined by size, composition and structure. In this work, we have reported a simple, rapid, single-step aerosol processing for the continuous synthesis of nanostructured particles having homogeneous composition and narrow size distributions, good crystallinity and fluorescence response. This paper presents the synthesis, optimization and characterization of hybrid Ag@Y2O3:Eu (9 at.% Eu3+) phosphor particles by means of spray pyrolysis method from water solutions of common nitrates precursors. The effect of silver concentration on particle structure, morphology and functional properties was specially evaluated. The as-prepared samples were additionally heated from 800 to 1200 °C/12 h under constant argon flow to avoid the silver oxidation. It was evident the cubic phase with Ia-3 symmetry as the principal one in all as-prepared and thermally treated samples. For the case high silver nitrate concentrations in precursor solutions a minority crystalline phase having Fm3m symmetry was identified. The luminescence emission spectra have been taken after excitation at 235 nm wavelength. It is evident the increase in the emission caused by the presence of metallic silver nanoparticles onto Y2O3:Eu3+ particle surface. It was also determined the silver concentration influence on the fluorescence response.