The majority of mitochondrial proteins imported from the cytosol. The main role in this process is played by protein complexes located in the outer and inner mitochondrial membrane. These outer membrane translocase complex TOM), and intimal translocation complexes (TIM). The components of an imported proteins recognize and enable their translocation across membranes or their incorporation into the film. The dynamic nature of both types of translocase allows the sorting of proteins with different mechanisms of imports. Besides an important role in protein import localized in the cytoplasm, space and matrix proteins. Disturbances in protein import into the mitochondria may be the cause of a new class of diseases of mitochondrial origin, which confirms the crucial importance of the import process of protein for the proper functioning of the mitochondria.