We studied whether tramadol administered at the time of wound closure can prevent postanaesthetic shivering. One hundred and fifty patients scheduled for general anaesthesia and surgery were randomly allocated and tramadol was administered intravenously at a dose of 2 mg.kg(-1) in the high-dose group, 1 mg.kg- in the low-dose group and 0.9% saline in the control group. In the high-dose group, 2% of patients had postanaesthetic shivering, compared to 4% in the low-dose group and 48% in the control group (p < 0.001 vs. tramadol groups). There was no delay in tracheal extubation after reversal of neuromuscular blockade. The incidence of adverse side-effects such as sedation and vomiting did not differ statistically and were clinically not significant. This study strongly supports the use of tramadol at wound closure for prevention of postanaesthetic shivering.