Mitochondria are key players in cell death following intrinsic and, in some cell types, extrinsic stimuli. The recruitment of the mitochondrial pathway results in mitochondrial dysfunction and release of intermembrane space proteins like cytochrome-c that are required in the cytosol for complete activation of effector caspases. Apoptotic shape changes of this organelle and the role of "mitochondria-shaping" proteins in cell death has attracted considerable attention. We present protocols to investigate how morphological changes of the mitochondrial reticulum regulate release of cytochrome-c, as evaluated quantitatively by an in situ approach, and changes in mitochondrial membrane potential measured in real time.