AbstractCarbondioxide pneumoperitoneum in laparoscopic appendicectomy is associated with adverse hemodynamic effects like increases in blood pressure, heart rate and systemic vascular resistance. These adverse effects are due to release of catecholamine and vasopressin. We conducted this randomized double blinded study to assess the effect of magnesium sulphate on attenuating these adverse hemodynamic responses. Materials and Methods: Sixty ASA I and II patients of either sex aged 20–60 years posted for elective laparoscopic appendicectomy were randomized into two groups of thirty patients each. Group M received magnesium sulphate 20 mg / kg intravenously before creating pneumoperitoneum. Group C received same volume of 0.9 % saline. Results: Systolic blood pressure, diastolic blood pressure and heart rate were significantly less in patients of Group M when compared to the placebo group. Conclusion: Magnesium sulphate given at a dose of 20 mg / kg before pneumoperitoneum attenuates adverse hemodynamic responses and ensures better hemodynamic stability during pneumoperitoneum created for laparoscopic surgery.