Abstract : BACKGROUND: Shivering is a common side effect of spinal anaesthesia. We evaluated the effectiveness of intravenous clonidine and tramadol for treating shivering during spinal anaesthesia. MATERIALS AND METHODS: A prospective, randomized, clinical controlled trial was carried out on 60 ASA grade I and II patients of either gender, aged 18-40 years, who were scheduled for elective lower abdomen and lower limb procedures under spinal anaesthesia. Patients with post-spinal intraoperative shivering of grade 3 or 4 lasting for at least 2 minutes were included in the study and randomly assigned to one of two groups, group C (n=30) received Inj. clonidine 50μg/kg i.v., and group T (n=30) received Inj. tramadol 0.5mg/kg i.v. when shivering was observed. Shivering control time, response rate, recurrence rate, and side effects were all measured. RESULTS: The average time taken for shivering to disappear in the clonidine group was 3.04 ± 0.72 minutes compared to 5.21 ± 0.95 minutes in the tramadol group. Tramadol patients had a higher rate of incomplete response and recurrence. Group C exhibited a larger rate of drop in heart rate and blood pressure, as well as higher sedation levels. The nausea and vomiting rates were greater in Group T. CONCLUSION: In patients receving spinal anaesthetia for surgery, clonidine was found to be more safe and effective than tramadol in reducing shivering.