The ideal intraoperative intravenous fluid in paediatric anaesthesia and surgery is still debatable. This is essential to overcome physiological changes to maintain safety and wellbeing of the patient. A new isotonic "balanced solution" (Sterofundin ® ISO) has been introduced to replace existing intraoperative fluid of choice (Ringer's Lactate). The study aimed to observe any changes in electrolytes and acid base after infusion of each study solutions and to evaluate any post infusion electrolytes and acid base differences between both study solutions. The double blinded randomized control trial involved 141 paediatric patients who were subjected to minor surgical procedure of less than 3 hours were randomized into Ringer's Lactate or Sterofundin ® ISO group. The electrolytes and acid base parameters were assessed at pre-infusion and post-infusion time. There were significant difference in glucose, potassium (K +) and chloride (Cl-) level between pre-infusion and post-infusion values with those given Ringer's Lactate. There were also significant different in pH, base excess, glucose, Calcium (Ca 2+), Chloride (Cl) and lactate level between pre-infusion and post-infusion values with Sterofundin ® ISO. When comparing the mean difference (pre-infusion and post-infusion) between Ringer's Lactate and Sterofundin ® ISO, calcium (Ca 2+) is the only electrtolyte which found to be significant (P=0.015) with the values of (Means±SD 0.005±0.07) mmol/L and (Means±SD 0.02±0.06) mmol/L respectively. Both study solutions showed variable effects of electrolytes and acid base parameters and no fluid was found to be superior in paediatric surgical patients underwent minor surgery of less than three hours.