The successful incorporation of ZnO nanoparticles in Pr3+-doped SiO2 using a sol-gel process is reported. SiO2:Pr3+ gels, with or without ZnO nanoparticles, were dried at room temperature and annealed at 600 A degrees C. On the basis of the X-ray Diffraction (XRD) results, the SiO2 was amorphous regardless of the incorporation of Pr3+ and nanocrystalline ZnO or annealing at 600 A degrees C. The particles were mostly spherical and agglomerated as confirmed by Field Emission Scanning Electron Microscopy. Thermogravimetric analysis of dried gels performed in an N-2 atmosphere indicated that stable phases were formed at a parts per thousand yen900 A degrees C. Absorption bands ascribed to H-3(4)-P-3((J = 0,1,2)), I-1(6) and D-1(2) in the UV-VIS region were observed from SiO2:Pr3+ colloids. The red cathodoluminescent (CL) emission corresponding to the P-3(0) -> H-3(6) transition of Pr3+ was observed at 614 nm from dried and annealed SiO2:Pr3+ powder samples. This emission was increased considerably when ZnO nanoparticles were incorporated. The CL intensity was measured at an accelerating voltage of 1-5 keV and a fixed beam current of 8.5 mu A. The effects of accelerating voltage on the CL intensity and the CL degradation of SiO2:Pr3+ and ZnO center dot SiO2:Pr3+ were also investigated using Auger electron spectroscopy coupled with an Ocean Optics S2000 spectrometer.