Endometriosis is a disease that involves dysfunction of mitochondria, imbalance of proliferation, and apoptosis. Coiled-coil-helix-coiled-coil-helix domain containing 2 (CHCHD2) is a major mitochondrial protein which could regulate the mitochondrial function and apoptosis in various tumor cells, promote migration and then lead to tumor progression. This study aimed to explore the role of CHCHD2 on endometriosis. We investigated the expression of CHCHD2 in ectopic and eutopic endometrium tissues of patients with endometriosis and normal endometrium tissues. Furthermore, CHCHD2 was downregulated to explore the corresponding change of mitochondrial function and morphology, mitochondrial-mediated apoptosis pathway, and proliferation and migration of ectopic endometrial stromal cells. Our results demonstrated that the mRNA and protein expression levels of CHCHD2 were significantly increased in eutopic and ectopic endometrium tissues compared with the normal endometrium tissues. The knockdown of CHCHD2 could cause mitochondrial dysfunction, including the opening of mitochondrial permeability transition pore, loss of mitochondrial membrane potential and the release of cytochrome c, and morphological damage. In addition, CHCHD2 down-expression could also lead to inhibition of cell proliferation, decrease of migration ability, and aggravation of mitochondrial-mediated apoptosis. Together, these findings suggest that increased expression of CHCHD2 in endometriotic tissues may contribute to the pathogenesis of endometriosis via regulating mitochondrial function and apoptosis, and CHCHD2 may be a potential target for interrupting the development of endometriosis.Keywords: CHCHD2; Endometrial stromal cells; Endometriosis; Mitochondria function; Mitochondrial-mediated apoptosis.