Objective: The objective of this study is to look for various and common electrolyte imbalances in critically ill children admitted to Paediatric Intensive Care Unit(PICU) and to study the outcome among those cases. Methods: This was a prospective observational study done on 84 critically ill children in the age group of 1 month to 12 years admitted in PICU of a tertiary care hospital. Under aseptic conditions venous samples were obtained for estimating serum levels of sodium, potassium, chloride, magnesium and phosphorus. The commonly occurring electrolyte imbalance was observed and the outcome is compared by morbidity, cure and mortality. Results: Electrolyte abnormalities were observed in 84 children(100%). Most common electrolyte abnormality observed was hypocalcemia in 70.2% cases (n=59). Morbidity was seen in 35.7% cases (n=30) and mortality associated with dyselectrolytemia was seen in 25.1% cases(n=21). Conclusion: This study showed increased incidence of dyselectrolytemia in critically ill children admitted to PICU. But the signs and symptoms are often difficult to recognize an electrolyte imbalance as the imbalances may be primary or secondary to underlying systemic illness. Early recognition and prompt management of electrolyte imbalances can lead to decrease in morbidity and mortality.