Magnesium sulfate is one of the most commonly used co-analgetics. Its antinociceptive effect is related to antagonizing NMDA (N-methyl-D-aspartate) receptors of the nervous system, has an anti-inflammatory effect by reducing the concentration of IL-6 (interleukin 6) and tumor necrosis factor alpha. In adult patients, the need for morphine in the perioperative period is reduced when magnesium infusion is used. In current guidelines for treatment of acute pain in children, magnesium sulfate may be considered as a co-analgetic. However, the strength of such a recommendation is low due to the lack of reliable scientific research confirming the effectiveness of magnesium infusion in the pediatric population. The aim of this study is to evaluate the efficacy of intravenous magnesium sulfate infusion on the opioid consumption, the circulatory, metabolic and hormonal response to intubation and surgical trauma during anesthesia for laparoscopic appendectomy in children.