Phosphor-converted white light-emitting diodes for indoor illumination need to be warm-white (i.e., correlated color temperature <4000 K) with good color rendition (i.e., color rendering index >80). However, no single-phosphor, single-emitting-center-converted white light-emitting diodes can simultaneously satisfy the color temperature and rendition requirements due to the lack of sufficient red spectral component in the phosphors’ emission spectrum. Here, we report a new yellow Ba0.93Eu0.07Al2O4 phosphor that has a new orthorhombic lattice structure and exhibits a broad yellow photoluminescence band with sufficient red spectral component. Warm-white emissions with correlated color temperature <4000 K and color rendering index >80 were readily achieved when combining the Ba0.93Eu0.07Al2O4 phosphor with a blue light-emitting diode (440–470 nm). This study demonstrates that warm-white light-emitting diodes with high color rendition (i.e., color rendering index >80) can be achieved based on single-phosphor, single-emitting-center conversion. Scientists have developed a yellow phosphor that can be used to provide a pleasing white light with a warm color temperature when combined with a blue light-emitting diode (LED) chip. Although YAG: Ce-based white LEDs show great promise as a highly efficient and long-lasting form of domestic lighting, their cool bluish-white light makes them undesirable for use in the home. Scientists from the USA and China have now shown that a new phosphor, Ba0.93Eu0.07Al2O4, when combined with a blue InGaN LED, provides a pleasing white light with a warm colour temperature of less than 4000K and a high colour-rendering index of more than 80. The phosphor has an orthorhombic structure and was manufactured by carbothermal reduction and vapour phase deposition in a tube furnace system. This work suggests that high-quality, warm-white lighting can be achieved using a combination of a single phosphor with single-emitting-center and a blue LED chip.