Background & objective: Perioperative shivering after spinal anesthesia for cesarean section is a common and unpleasant complication. Currently pethidine is being used but the search continues to look for other agents with faster action and with fewer side effects. Tramadol is a potential anti-shivering drug with modulation of central thermoregulation. We compared the efficacy of tramadol versus pethidine in the treatment of perioperative shivering of patients undergoing cesarean section under spinal anesthesia. Methodology: After institutional ethical review committee approval, 42 patients undergoing cesarean section under spinal anesthesia, who experienced shivering, were randomized into two groups, Group T (n = 21) received 1 mg/kg tramadol and Group P (n = 21) received 0.5 mg/kg pethidine. The outcome measures included the time taken to cessation of shivering after the medication, recurrence of shivering and the incidence of side effects. Results: The parturients with mean age 30.2 ± 5.2 y and body mass index (BMI) 29.9 ± 4.9 kg/m2 were recruited with comparable data between the two groups. Median time taken from drug administration until cessation of shivering of the tramadol group was faster than the pethidine group (7 min vs 13 min, P = 0.049). However, there was no significant difference in terms of the number of recurrences of shivering (P = 0.606) and incidence of nausea (P = 0.19) between the two groups. Conclusion: Intravenous tramadol has faster alleviation of perioperative shivering than intravenous pethidine in the treatment of perioperative shivering. Key word: Tramadol; Pethidine; Cesarean section; Shivering; Anesthesia, Spinal Citation: Yaakop AF, Hassan MH, Omar SC, Mazlan MZ, Mukmin LA, Hassan WNW. Tramadol vs pethidine to control perioperative shivering in cesarean section under spinal anesthesia: a double-blind study. Anaesth. pain intensive care 2022;26(3):283-290; DOI: 10.35975/apic.v26i3.1893 Received: March 15, 2022, Reviewed: March 27, 2022, Accepted: May 09, 2022