BACKGROUND The haemodynamic surge in laparoscopic surgery following carbon dioxide insufflations can be attenuated by various drugs. Dexmedetomidine, a selective-alpha-agonist depresses central sympathetic outflow producing sedation, decreased analgesic requirement, is approved by USFDA for mechanically ventilated patients in ICU for a period of <24 hours. One of its "off label" uses is attenuation of Hemodynamic changes in laparoscopic surgery. Parenteral magnesium sulphate has been used as an antiarrhythmic and antiseizure drug in preeclampsia. It also has analgesic action on NMDA receptor, inhibits catecholamine release from peripheral nociceptors and attenuates vasopressor mediated vasoconstriction. A study was conducted to assess and compare the effects of these drugs. We wanted to study the relative efficacy of infusions of dexmedetomidine & magnesium sulphate on attenuation of hemodynamic responses in laparoscopic surgery under general anaesthesia. METHODS A prospective, double blind, randomized, comparative study was conducted on a total of 105 patients in a tertiary care teaching hospital. The three groups (n=35) were: Control (Group-C), Dexmedetomidine (Group-D), and Magnesium sulphate (Group-M). RESULTS Heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure were significantly lower with Dexmedetomidine group than Magnesium sulphate group at all intervals (p<0.05) The MgSo4 group however showed significantly (p<0.05) better haemodynamic control at 30 minutes compared to the control group. CONCLUSIONS Intravenous infusion with Dexmedetomidine for laparoscopic surgery under general anaesthesia is more effective than Magnesium sulphate in attenuating the cardiovascular effects of pneumoperitoneum.