Background: Crif-1 is a mitochondrial protein which regulates mitoribosome-mediated synthesis and insertion of mitochondrial oxidative phosphorylation (OXPHOS) polypeptides into the mitochondrial membrane in mammals. Objectives: To investigate whether Crif-1 affects hair growth. Methods: We created K15-Cre;Crif-1fl/fl conditional knockout mice. Results: Crif-1 gene was conditionally deleted out in hair follicle bulge by application of RU486. The hair growth of K15-Cre;Crif-1fl/fl conditional knockout mice was significantly inhibited compared to that of wild type littermates. Interfollicular epidermis of K15-Cre;Crif-1fl/fl conditional knockout mice was thinner and less proliferative than wild type littermates. Conclusion: These results suggest that mitochondrial dysfunction in hair bulge stem cells is important in hair growth.