Objective: This study is conducted to assess the analgesic effects of intravenous magnesium sulphate (50 mg/kg) in hip surgeries under spinal anaesthesia. Methods: This prospective, randomised, double blinded control study was done on 60 patients posted for hip surgeries (Dynamic hip screw fixation, Proximal femur nailing and Hemiarthroplasty) under spinal anaesthesia. The patients were randomly divided into two groups with 30 patients each. Group S (Study) received magnesium sulphate 50 mg/kg intravenously in 250 ml Normal saline, 15 minutes before spinal anaesthesia and group C (Control) received same volume of normal saline. Hemodynamic variability, duration of analgesia and analgesic requirements were evaluated upto 12 hours after surgery. (30 minutes, 2, 4, 8 and at 12 hours). Results: Postoperative pain scores were significantly lower in Group S (p<0.05) at 2nd hour after surgery and was not significant at other time intervals. Time to first analgesic requirement was significant (p=<0.005) between two groups. Rescue analgesic requirement was lower in Study group compared to Control group, and was statistically significant (p=0.009). The two groups had no significant differences with regards to hemodynamic variability and had no side effects. Conclusion: Intravenous magnesium sulphate 50 mg/kg when given as a bolus reduced the postoperative pain and decreased the need of rescue analgesics after spinal anaesthesia for hip surgeries.