In Chapters 4-6, the crystal structure and photoluminescence properties of nitride phosphors were presented and discussed. Some of these phosphors show very broad excitation spectra, useful emission colors, high quantum ef”ciency, and small thermal quenching, so that they are very attractive for use as wavelength conversion materials in white LEDs. In comparison to traditional phosphors (aluminates, silicates, –uorides, oxysul”des, etc.), nitride phosphors exhibit superior photoluminescence properties and reliability, including abundant emission colors, stronger absorptions of blue light, higher chemical stability, and smaller degradation under thermal and irradiation attacks. These excellent properties of nitride phosphors allow for the production of white LEDs with tunable color temperatures, high color rendition, high luminous ef”ciency, small variations in chromaticity coordinates, and a long lifetime. In this chapter, white LEDs utilizing nitride phosphors will be introduced.