BACKGROUND Subarachnoid block (SAB) is a versatile regional anaesthesia technique for lower limb surgeries. Hypothermia (shivering) is a frequent, potentially serious event after spinal anaesthesia which can lead to severe complications. Several methods are used to minimize perioperative hypothermia and shivering. METHODS A hospital based prospective study was conducted in Government Medical College, Thrissur, over 12 months from January 2019 to January 2020. 260 American Society of Anesthesiologists physical status I and II patients undergoing elective surgeries under spinal anaesthesia were included. Prior to surgery patients were randomly allotted into two groups; Group 1 and Group 2. Group 1 patients were pre-warmed for 20 minutes and Group 2 were not pre-warmed. Measurement of body temperature, vital signs and shivering score was taken peri-operatively. Occurrence of hypothermia and shivering was observed intraoperatively and one hour postoperatively. RESULTS Baseline demographic data of the 2 groups was comparable. Temperature was persistently lower at all points except baseline in Group 2 compared to Group 1. Of those pre-warmed, 4.6 % and amongst those not pre-warmed, 65.4 % had shivering. Difference is statistically significant with chi square of 105.5 and p value <.001. CONCLUSIONS Incidence of hypothermia and shivering is found to be less in the pre-warmed. Hence, forced pre-warming has significant influence on hypothermia and shivering. KEY WORDS Subarachnoid Block, Pre-Warming, Hypothermia, Shivering.