People are sleeping less in modern societies. It is said that short duration of sleep could play a role in the etiology of not only diabetes mellitus (DM) but also hypertension. Sleep disorders inducing sleep fragmentation and sleep deprivation, such as insomnia, obstructive sleep apnea syndrome (OSAS), and periodic limb movement disorder (PLMD), have been suggested to be independent risk factors for hypertension. OSAS is associated with a range of cardiovascular complications, in particular hypertension. All of hypertensive patients should be routinely screened for possible sleep disorders.