The Er 3+ and Er 3+ /Yb 3+ co-doped CeO 2 powders have been prepared by a urea combustion route. The structural, morphological, compositional and vibrational analysis of the Er 3+ :CeO 2 and Er 3+ /Yb 3+ :CeO 2 powders have been studied by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray and Fourier transform infrared spectroscopy. The optical and luminescence properties of Er 3+ :CeO 2 and Er 3+ /Yb 3+ :CeO 2 powders have been studied by using laser excited spectroscopy. The effects of Yb 3+ doping on up-conversion luminescence of Er 3+ co-doped CeO 2 powders were studied. The ratio of red to green intensity is decreased in Er 3+ :CeO 2 whereas the ratio is increased in Er 3+ /Yb 3+ :CeO 2 powders with increase of power. The effect of co-doping with the Yb 3+ ions on the visible luminescence of Er 3+ and the energy transfer mechanism responsible for the variation in the green and red intensity are discussed. The results indicate that these materials may be suitable for display and light emitting devices.