ABSTRACTHost metabolism reprogramming is a key feature ofMycobacterium tuberculosis(Mtb) infection that enables the survival of this pathogen within phagocytic cells and modulates the immune response facilitating the spread of the tuberculosis disease. Here, we demonstrate that a previously uncharacterized secreted protein fromMtb, Rv1813c, manipulates the host metabolism by targeting mitochondria. When expressed in eukaryotic cells, the protein is delivered to the mitochondrial intermembrane space and promotes the enhancement of host ATP production by boosting the oxidative phosphorylation metabolic pathway. Furthermore, the release of cytochromecfrom mitochondria, an early apoptotic event in response to short-term oxidative stress, is delayed in Rv1813c-expressing cells. This study reveals a novel class of mitochondria targeting effectors fromMtbthat might participate in host cell metabolic reprogramming and apoptosis control duringMtbinfections.IMPORTANCEIn this article, using a combination of techniques (bioinformatics, structural biology, and cell biology), we identified and characterized a new class of effectors present only in intracellular mycobacteria. These proteins specifically target host cell mitochondria when ectopically expressed in cells. We showed that one member of this family (Rv1813c) affects mitochondria metabolism in a way that might twist the immune response. This effector also inhibits the cytochromecexit from mitochondria, suggesting that it might alter normal host cell apoptotic capacities, one of the first defenses of immune cells againstMtbinfection.