Ambulatory blood pressure monitoring (ABPM) is a major innovation in the history of hypertension diagnosis. In clinical practice, the most well established indication for using ABPM is to identify patients who have high BP readings in the office but normal readings during usual daily activities outside of this setting or vice versa, and to identify varying 24-h BP profiles. However, in recent years, there has been increasing interest in BP values during sleep, and nocturnal BP is now recognized to be superior to daytime BP in predicting fatal and nonfatal cardiovascular events (stroke, myocardial infarction, and cardiovascular death), especially in medicated patients. The current direction in the management of hypertension is toward earlier and lower BP control for 24 hours, including the nocturnal and morning periods. Therefore, it may be of great significance to pay attention to the management of nocturnal blood pressure so as to reduce the increased cardiovascular risks. Information of nocturnal hypertensive patients defined by ABPM was prospectively registered nationwide, and then to investigate whether there was difference in cardiovascular prognosis according to the control of ambulatory nocturnal blood pressure.