Homogeneous assay for cell viability, proliferation, cytotoxcity and high-throughput screen for anticancer agents. Key Features: Safe. Non-radioactive assay (cf. ³H-thymidine incorporation assay). Sensitive and accurate. As low as 100 cells can be accurately quantified. Time efficient. High-throughput assay in 96-well and 384-well plates allows simultaneous processing ten of thousands of samples per day. Homogeneous and convenient. A single reagent and "mix-incubate-measure" type assay. No wash and reagent transfer steps are involved. Robust and amenable to HTS. Z factors of 0.6 to 0.9 are routinely observed in 96-well and 384-well plates. Can be readily automated on HTS liquid handling systems. Method: FL530/590nm. Samples: Cell culture. Species: All. Procedure: Assay takes 1-5 hrs, hands-on time 30 min. Kit size: 5000 tests. Detection limit: 100 cells.