Background and objective: This placebo-controlled study was performed to evaluate the efficacy of dexmedetomidine compared with meperidine and placebo in preventing postanaesthetic shivering. Methods: We studied 120 patients (ASA I-II) scheduled for elective abdominal or orthopaedic surgery of about 1-3 h duration. Forty patients in each group randomly received 1 mu g kg(-1) of dexmedetomidine, 0.5 mg kg(-1) of meperidine or saline 0.9% as placebo, intravenously (i.v.). Mean arterial pressure, heart rate, oxygen saturation and central body temperature were measured. Extubation, awakening and orientation times, shivering, pain, recovery and sedation scores were recorded. Results: Postanaesthetic shivering was seen in 22 patients in the placebo group, four patients in the meperidine group and six patients in the dexmedetomidine group. Sedation scores were significantly higher in the dexmedetomidine group compared with meperidine and placebo groups. Both dexmedetomidine and meperidine caused a significantly prolonged extubation and awakening time compared with placebo. Also, dexmedetomidine caused a significantly prolonged orientation time compared with other two groups. Conclusion: Intraoperative intravenously administration of dexmedetomidine 1 mu g kg(-1) reduces postanaesthetic shivering as does meperidine 0.5 mg kg(-1) in patients after major surgery.