The present work addresses the synthesis and characterization of red emitting Gd2-xEuxO3 nanocrystalline phosphors by a modified sol-gel based method. The effects of the annealing temperature and atomic fraction of Eu3+ ions, 'x', on the structural and luminescence properties of the produced oxides have been systematically investigated. X-ray diffraction analyses revealed that crystalline cubic-Gd 2O3 host structure was obtained when the intermediates (x=0.01-0.30) were annealed at different temperatures in air. Photoluminescence spectra of doped Gd2O3 powders showed all transitions of Eu2+ species, being the 5D0→ 7F2 transition the most intense. On a common sample-weight basis, the highest photoluminescence intensity was obtained at 'x'= 0.15. The energy transfer from host to dopant was verified for all evaluated 'x' values, which suggest the actual incorporation of Eu species into the Gd-oxide lattice. It was also found that the photoluminescence intensity was strongly dependent on the annealing temperature and dopant concentration. © 2008 Materials Research Society.