Ringer lactate (RL) is a commonly used intravenous fluid during surgery and has been found to have decreased possibility of producing hyponatremia although it is a slightly hypotonic solution.Plasmalyte is an isotonic fluid which has been shown to maintain electrolyte balance and prevent hyponatremia as well as hyperchloremic acidosis in adult population.However plasmalyte has been less frequently used in paediatric population.Therefore this study is planned with the aim of comparing intravenous fluids, ringer lactate and plasmalyte in the perioperative period regarding the incidence of hyponatremia produced by these solutions, their effect on electrolytes and blood gases in children undergoing elective surgery.