Post traumatic stress resulting from an intensive care unit(ICU) stay may be prevented by adequate level of sedation and analgesia. Aims of the study were reviewing the current practices of sedation and analgesia in our ICU setup and to assess level of sedation and analgesia to know the requirement of sedative and analgesics in mechanically ventilated ICU patients. This prospective observational study was conducted on 50 consecutive mechanically ventilated patients in ICU over a period of 6 months. Patient's sedation level was assessed by Ramsay Sedation Scale (RSS = 1 : Agitated; 2,3 : Comfortable; 4,5,6 : Sedated) and pain intensity by Behavioural Pain Scale (BPS = 3 : No pain, to 16 : Maximum pain). BPS, mean arterial pressure(MAP) and heart rate(HR) were assessed before and after painful stimulus (tracheal suction). Although no patient had received sedative and analgesics, mean Ramsay score was 3.52 +/- 1.92 with 30% patients categorized as 'agitated', 12% as 'comfortable' and 58% as 'sedated' because of depressed consciousness level. Mean BPS at rest was 4.30 +/- 1.28 revealing background pain that further increased to 6.18 +/- 1.88 after painful stimulus. There was significant rise in HR (10.30%), MAP (7.56%) and BPS (40.86%) after painful stimulus, P<0.0001. The correlation between BPS and Ramsay Score was negative and significant (P<0.01). We conclude that there should be regular definition of the appropriate level of sedation and analgesia as well as monitoring of the desired level, using sedation and pain scales as a part of the total care for mechanically ventilated patients.