Night shift work is associated with a disruption of circadian rhythms, where a person’s internal body clock is in conflict with the rotating shift schedule. The circadian rhythm of the human body is characterized with an alternating cycle of sleep and awake.[1] Among healthy subjects, sleep tends to occur during a particular phase of circadian cycle.[2] It is possible that the circadian sleep propensity rhythm and hormonal rhythm are under influence of circadian pacemaker as well as sleep habit.[3] Most rhythms are driven by an internal biological clock located in the hypothalamic suprachiasmatic nucleus and can be synchronized by external signals such as light-dark cycles.[4, 5,] In the present prospective study, we examined the 24 hours chronomics of BP/HR in night shift workers and to find out the possible correlation with 6-sulfatoxy melatonin. 62 healthy nursing professionals, aged 20-40 year, performing day and night shift duties were recruited from the Trauma Center, KGMU. Ambulatory blood pressure and heart rate were recorded at every 30 min intervals while awake and each hour in night time synchronically with circadian pattern of urinary melatonin during night and day shift duties. Highly Significant difference was found in double amplitude (2DA) of blood pressure between night and day shift (p<0.001). Circadian patterns of systolic double amplitude (Night shift: 24.50 ± 15.07 vs Day shift: 35.07 ± 16.01) (p<0.001) was higher in day shift as compare to night shift, diastolic double amplitude (Night shift: 18.96 ± 10.96 vs Day shift : 24.85 ± 11.70) (p<0.001) was also increased in day shift than night shift. A circadian pattern of systolic and diastolic 2DA was higher in day shift as compare to night shift. Acrophase of systolic, diastolic blood pressure and heart rate were altered (reversed) during night shift. During night shift, hyperbaric index (HBI) of mean systolic blood pressure was found to be increased at 00-03 am (midnight) while during day shift, peak was found at 06-09 am. It exhibits the desynchronization during night shift and entrainment of circadian rhythm in day shift. Peak melatonin was to be found in early morning as compared to mid night in night and day shift. Altered melatonin at night and in the morning time was related with the symptoms of sleep deprivation.