AllStars Hs Cell Death Control siRNA is a blend of highly potent siRNAs targeting ubiquitously expressed human genes that are essential for cell survival. Knockdown of these genes induces a high degree of cell death, which is visible by light microscopy. Transfection efficiency can be quickly estimated by simply observing cells by straightforward light microscopy 48–96 hours after transfection of AllStars Hs Cell Death Control siRNA, avoiding the need for any complex or laborious downstream assay. AllStars Hs Cell Death Control siRNA is a useful tool for siRNA transfection optimization and can be used routinely as a positive control.