The objective of this study is to explore whether diabetes play roles on histopathological change of Achilles tendon in leptin-deficient mice. Ob mice (specific-pathogen free SPF) were identified at 10 days after birth and killed via dislocation of cervical spine at 12 weeks. Achilles tendon was isolated as quickly as possible and histopathological changes were investigated. Degeneration of tendinocytes, vascular proliferation, chondrocyte-like tendon cell and ruptures at insertion areas were observed. We conclude that diabetes is associated with histopathologic change in Achilles tendon of ob mice.