Lutetium and yttrium oxides are promising scintillating materials suitable for use in medical planar X-ray imaging and mammography. In this paper the procedure for preparation of europium doped mixed lutetium-yttrium oxide nanopowders using polymer complex solution synthesis method is presented. Detailed information on nanopowder phase, morphology and crystallinity are obtained using X-ray powder diffraction. SEM and TEM while optical properties are investigated by photoluminescence and radioluminescence measurements. Constituting nanoparticles are 20-40 nm in size, and have excellent structural ordering in cubic bixbyite-type. Unit cell parameter, ionic coordinates, crystal coherence size and microstrain are determined from Rietveld analysis. All powders show strong Eu3+-characteristic red emission, with an average D-5(0) emission lifetime of 1.5 ms. Radioluminescence efficiency is about 15% of the commercial micron-sized Gd2O2S:Eu3+ powder while negligible level of afterglow is found. (C) 2010 Elsevier B.V. All rights reserved.