The luminescence of the vanadate garnet, Ca2NaMg2V3O12, activated with trivalent europium is evaluated and discussed as a potential ultraviolet light-emitting diode (UV-LED) phosphor. This single phosphor is capable of converting the ultraviolet emission of a UV-LED into white light with good luminosity and color-rendering index. We have evaluated the luminescence of this material at elevated temperatures, because the junction temperatures of typical LEDs can be greater than 100 degrees C. There is significant thermal quenching of this phosphor and emission color shift at T > 100 degrees C. This is attributed to energy migration and transfer to nonradiative traps and Eu3+ within the host lattice. These implications on the use of this phosphor in UV-LED based light sources is also discussed. (c) 2005 The Electrochemical Society. All rights reserved.