The DNA repair transcriptomes of the liver of humans, naked mole rats and mice were compared. The maximum lifespans of humans, naked mole rats, and mice are respectively ~120, 30 and 3 years. The longer-lived species, humans and naked mole rats, expressed DNA repair genes at a higher level than did mice. In addition, several DNA repair pathways in humans and naked mole rats were up-regulated compared with mice. These findings suggest that increased DNA repair makes for greater longevity. The findings are consistent with the DNA damage theory of aging.