Supernumerary, old or damaged cells of multicellular organisms are eliminated by apoptosis – programmed cell death. Apoptosis is accompanied by series of characteristic morphological and biochemi- cal events. The cell activates a cascade of cysteine proteases – caspases, that digest target proteins. Nucleases are also activated, which together leads to irreversible cell damage within few hours. Mitochon- dria are the cell compartment that integrates signals from different apoptotic pathways activated by ischemia, heat shock or growth hormones depletion. Mitochondria play the primary role in coordination and amplification of cell autodegradation signals. They regulate apoptosis by sequestration of pro- and antiapoptotic proteins. Perturbation of activation or execution of apoptosis is characteristic feature of cancer cells.