We studied the behavior and neuroendocrine regulation under social disruption stress of C57BL/6J mice in which mitochondria were substituted by mitochondria from AKR/J or FVB/N strains. C57BL/6J-mt(FVB/N) mice were significantly more anxious in the elevated plus-maze test than C57BL/6J-mt(AKR/J) and C57BL/6J mice at base line. In addition, they showed a reduced corticosterone response and an activation of serotonergic and dopaminergic neurotransmitter systems after repeated challenge, i.e., social defeat and elevated plus-maze test. Our findings suggest that mitochondrial variations could affect anxiety-like behavior as well as corticosterone and neurotransmitter response to psychological stress.