Background: Blood pressure (BP) is volatile in nature and also it affects post-operative outcomes therefore, regular perioperative BP monitoring is essential. Intraoperative variability of BP is permitted in range and proportion to baseline BP according to various guidelines. Pre-operatively BP is measured many times and it is highly variable. In this study we attempt to predict which pre-operative BP can be used as reference during intraoperative monitoring.       Methods: This observational study was conducted at hamidia hospital, Bhopal. 260 normotensive patients undergoing elective surgery who got clearance during PAC were enrolled. BP was measured by gold standard mercury sphygmomanometer in PAC clinic (PAC1), review PAC one day prior to surgery (PAC2), morning BP in preoperative room (POR) and inside OT room (IOR) before surgery.    Results: In 260 enrolled patients males were slightly predominant 52.31%. Mean age was 34.68±11.63 years. Mean of Systolic BP (SBP) during PAC1, PAC2, Morning BP in POR and IOR prior surgery were 122.85±8.24, 118.18±8.08, 123.06±8.24 and 135.73±10.24 respectively and was significant (P<0.001). Mean of heart rate (HR/minute) during PAC1, PAC2, Morning BP in POR and IOR prior surgery were 79.77±7.22, 78.90±7.44, 80.40±7.49 and 89.15±7.60 respectively and was significant (P<0.001). Conclusions: Aaaaaa Due to stress of surgery SBP and HR were significantly higher in IOR just prior surgery. Also, BP of PAC2 at ward was lowest though not significantly lower than BP in PAC1 or POR. Thus, BP of PAC2 can be used as an ideal reference BP but larger study is required for further generalization. Keywords: Systolic Blood Pressure, Diastolic Blood Pressure, Mean Blood Pressure