The aim of this prospective, randomized and double-blind study was to assess the effects of a high dose of the analgesic tramadol administered at the conclusion of surgery on extubation time, sedation, and post-anaesthetic shivering. Forty adult patients, ASA physical status I or II, underwent laparoscopic surgery of about 1 h duration and received a standardized anaesthesia that was maintained with isoflurane in O2/N2O. Tramadol 3mg kg−1 (n=20) was administered intravenously at the beginning of wound closure, and was compared with saline (n=20). Post-anaesthetic shivering did not occur in any patient who received tramadol, whereas it occurred in 60% of the control group ( P<0.001). There were no adverse effects on time to extubation and sedation, and discharge-ready time was shorter in the tramadol group (P<0.05 compared with control). Pain scores in the post-an-aesthesia care unit (PACU) were statistically not different between the two groups, but significantly more supplemental medication was administered in the control group to treat shivering and/or pain. In conclusion, administration of a high dose of tramadol at the end of surgery prevents post-anaesthetic shivering without prolongation of extubation time, and shortens the PACU/discharge-ready time.