Growing evidence provided by many observational studies has established a strong link between decreased sleep duration and poor glucoregulation. Sleep deprivation and poor sleep quality induce insulin resistance and decrease glucose tolerance in healthy individuals. However, the influence of poor sleep quality on glycemic control of patients with Type 1 diabetes mellitus (T1DM) is unknown. Persistent sleep deprivation among patients with T1DM has been reported, and this sleep loss can be attributed in part to nocturnal hypoglycemia. Nocturnal iatrogenic hypoglycemia is a limitation of current intensive insulin therapies. Although severe hypoglycemia is associated with adverse events such as seizures and death, less severe nocturnal hypoglycemia has been linked to broad range of adverse consequences, both acutely and long term. Hypoglycemia stimulates the sympathetic nervous system as a stress response, leading to the stimulation of the hypothalamic-pituitary-adrenal axis (HPA). This results in a counter regulatory hormone cascade, which elicits an excessive cortisol secretion, which is known to cause sleep disturbance and could impair glucose homeostasis after the hypoglycemic event. The hyperinsulinemia in T1DM patients promotes HPA hyperactivity as well, which is also associated with impaired sleep quality by leading to sleep fragmentation, decreased slow wave sleep and shortened sleep duration. Sleep disturbances due to nocturnal hypoglycemia can exacerbate HPA axis dysfunction, adversely affecting the sleep-wake cycle.