Caspases are critical regulators of the apoptotic program, responsible for the harmonic dismantling of the cell. Cell death can occur by way of different options (necroptosis, necrosis, extreme autophagy) but once caspases are fully engaged it will take the apoptotic route. Hence, in general, caspase activity is inversely proportional to cell viability. Caspase activation can be measured by means of different techniques. Here, we describe three different methodologies to measure/observe caspase activation. Two approaches are recommended for studies on the whole cell population, whereas the third one is designed for visualizing caspase activation in single live cells.