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.