Sleep is a basic human need and is essential for good quality of life, good health. In fact, humans spend one third of their life time in sleeping or attempting to do so. However, sleep is not given due importance in intensive care unit (ICU)'s, although it is critical in healing process. Patient's usually get admitted to the hospital few days prior to the surgery, for complete evaluation, depending on the procedure planned. Hospital environment being, an entirely new place for inpatients, will invariably affect their sleep. Sleep deprivation is one of the major sources of anxiety and stress in all the patients during ICU stay. This means that most of patients are sleep deprived, by the time they are admitted to ICU. The negative effects of sleep deprivation include postoperative brain dysfunction like inattention, restlessness, hallucinations, agitation, aggressiveness. The degree of cognitive impairment may range from subtle derangements in attention, reason, clarity of thought and capacity of decision making to confusion and delirium. Sleep deprivation can also induce hypertension, fatigue, metabolic disorders, cerebrovascular and cardiovascular disease