Apoptosis, namely programmed cell death, is a fundamental mechanism involved in both organogenesis and tissue homeostasis. Since this process is genetically controlled, its defective regulation plays a role in the pathogenesis of several diseases including inflammatory and degenerative disorders, autoimmunity and neoplasia. Several methods have been suggested to identify the cellular events including the modification of cell size, cytoplasmic condensation and nuclear degradation occurring during this phenomenon. The cell morphologic changes can be observed in detail by electronic microscopy, while the chromatin cleavage is well detected by both electrophoretic and flow cytometry techniques, using various fluorochromes able to bind specifically the double-stranded DNA. Here we review the different techniques to evaluate apoptosis with respect to their sensitivity in both qualitative and quantitative analyses.