Mitochondrial Ca2+ handling plays an important role in energy production and various cellular signaling processes. Mitochondrial Ca2+ uptake is regulated by the mitochondrial Ca2+ uniporter (MCU), at least one non‐MCU Ca2+ channel and possibly a mitochondrial ryanodine receptor. Two distinct mechanisms mediate Ca2+ outward transport, the Na+‐dependent (mNCX) and the Na+‐independent Ca2+ efflux. In recent years we gained more insight into the regulation and function of these different Ca2+ transport mechanisms. However, the precise physiological role and the molecular structure of all mitochondrial Ca2+ transporters and channels still has to be determined.