The ONE-Glo™ Luciferase Assay System provides a highly sensitive, robust, homogeneous assay for detection of firefly luciferase reporter gene expression in mammalian cells. Ideally suited for high- and ultrahigh-throughput applications, the ONE-Glo™ Assay contains a new luciferase substrate, resulting in a reagent that is more stable, more tolerant to sample components, and has less odor than standard luciferase assay reagents. These features ensure that the ONE-Glo™ Assay provides robust performance and also eliminates many of the handling inconveniences experienced using other reporter assays in a high-throughput setting.