Evidence from well-defined cohort studies has shown that short sleep, through sleep fragmentation caused by obstructive sleep apnea (OSA) or behavioral sleep curtailment because of lifestyle choices, is associated with increased incidence of diabetes. In this report, we review epidemiologic and clinical data suggesting that OSA is involved in the pathogenesis of altered glucose metabolism. Evidence suggesting increased risk of developing diabetes resulting from curtailed sleep duration is also considered. Proposed mechanisms explaining associations between short sleep and diabetes are examined and clinical management of OSA among patients with diabetes is discussed.