AbstractMethods for assessing mammalian cell death are presented in this article, which is divided into six sections: (1) a brief overview of cytotoxicity and pathways of cell death; (2) a method to measure cell death using lactate dehydrogenase (LDH) release as a marker of membrane integrity; (3) a flow cytometry method that simultaneously measures two types of cell death, necrosis and apoptosis; (4) use of fluorescence microscopy and nuclear morphology to assess apoptosis and necrosis; (5) the use of multi‐well plates and high‐content analysis imaging systems to assess nuclear morphology; and (6) a discussion of the use of cytotoxicity assays to determine the mechanisms of cell death. © 2021 Wiley Periodicals LLC.Basic Protocol 1: Measurement of plasma membrane integrity and viability using LDH releaseBasic Protocol 2: Measurement of necrosis and apoptosis using flow cytometryBasic Protocol 3: Determination of nuclear morphology and membrane integrityAlternate Protocol 1: Assessment of nuclear morphology and membrane integrity using DAPI and PIAlternate Protocol 2: Assessment of nuclear morphology using multi‐well platesBasic Protocol 4: Measurement of time‐dependent toxicity using cell death markers