The main aim of a perioperative fluid therapy is to maintain or normalize the patient’s homeostasis. Small children have higher fluid volumes, metabolic rates and fluid needs than adults. Therefore, short perioperative fasting periods (formula milk 4 hours, breast milk 3 hours, clear fluids 1 hour) are important to avoid iatrogenic dehydration, hypotension, ketoacidosis and uncooperative behavior. Balanced electrolyte solutions with 1–2.5% glucose are favored for intraoperative maintenance infusion. Glucose- free balanced electrolyte solutions should then be added as needed to replace intraoperative fluid deficits or minor blood loss. Gelatin solutions or hydroxyethyl starch are useful in hemodynamically unstable patients or those with major blood loss, especially when crystalloids alone are not effective and blood products are not indicated. The monitoring should focus on the maintenance or restoration of a stable tissue perfusion.In nonsurgical or postoperative children, balanced electrolyte solutions should be used instead of hypotonic solutions, both with 5% glucose, as recent clinical studies and reviews showed a lower incidence of hyponatremia.