A sol-gel method was developed to obtain cerium-, gadolinium-(co)activated yttrium aluminum garnet (YAG:Ce,Gd) phosphor. The composite was obtained by incorporating YAG:Ce,Gd powder in poly(methyl methacrylate) (PMMA) matrix in the presence of tetrahydrofuran (THF). Sample characterization was performed using Fourier transform infrared spectrometry, X-ray diffraction, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy, and fluorescence spectroscopy. Results showed a garnet pure phase at 1000 C, a nanoscale phosphor with spherical morphology and a good dispersion in PMMA matrix without structural modification of YAG:Ce,Gd in the composite. This type of phosphor can be used for all commercial blue chips and YAG:Ce,Gd/PMMA composite is a good candidate for white light-emitting devices.