Purpose: we evaluated the effects of magnesium sulphate infusion on anesthetic requirement, early recovery and postoperative analgesia in desflurane-remifentanil-based, balanced anaesthesia. Methods: 60, ASA (American Society of Anesthesiologists) group 1-2 patients who were scheduled for laparoscopic cholecystectomy were randomly divided into two groups. Before anesthesia, the magnesium-treated group (n = 30) received a 15 min infusion of 40 mg/kg of magnesium sulphate followed by 10 mg/kg/h by continuous i.v. infusion during the operation. The same volume of isotonic saline was administered to the control group (n = 30). Anesthesia was induced with propofol, remifentanil and vecuronium, and maintained with desflurane 3-6%, O 2 /air and remifentanil infusion. Desflurane was titrated to maintain BIS (bispectral index) values of 40-60. The times from cessation of anesthesia to spontaneous breathing, eye opening, extubation, reaching BIS 70, and Aldrete scores were recorded. After surgery, patients received a patient-controlled, morphine analgesia device. Results: demographic variables were similar. During the 15 min infusion of magnesium sulphate, the BIS value was significantly lower in the magnesium sulphate-treated group. The amounts of propofol and desflurane used were less in the magnesium sulphate-treated group, by 18% and 22% respectively (p<0.05). The groups did not differ with respect to the time taken to reach BIS 70, spontaneous breathing, eye opening and extubation. Alderete and VAS (visual analogue scale) pain scores, and total morphine consumption were significantly lower in the magnesium sulphate-treated group. There were no differences in side effects, but the rate of re-intubation was higher in the group receiving magnesium sulphate (p = 0.03). Conclusion: perioperative use of magnesium sulphate reduced propofol and desflurane consumption, and the postoperative morphine requirement, while causing a delay in recovery by decreasing the Aldrete score.