BaMgAl10O17 co-doped with Eu2+ and Mn2+ was synthesized in a solid-state reaction and their luminescence properties were investigated as functions of the concentrations of the sensitizer and activator. The energy transfer from Eu2+ to Mn2+ was mainly of the resonance-type via an electric dipole-quadrupole interaction. Additionally, the addition of various fluxes such as AlF3 and BaF2 in the synthesis improves the moist stability. This is particularly important for the phosphor in white light-emitting diodes (LEDs). The white LEDs with a color rendering index of 95 were fabricated by coating the synthesized phosphors on a UV LED chip to verify the real application capability. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3454755] All rights reserved.