Aims: The present study has been planned to study the serum electrolyte levels and acid–base status in children of acute watery diarrhea with dehydration. Methodology– The study was a hospital–based Observational Study involved 200 Children below 5 years of age presenting with acute diarrhoea with Dehydration requiring hospitalization. ABG analysis and serum electrolytes were conducted during the study period of 1 year (July 2017–June 2018). Results– Out of 200 children enrolled, hyponatremic dehydration was seen in 51 (25.5%), Hypokalemia in 51 (25.5%) and metabolic acidosis in 27 (13.5%) children. Conclusion– Electrolyte imbalance and acid–base imbalance (metabolic acidosis) were seen in children with acute watery diarrhea with dehydration, so while managing these children all these factor should be considered for optimising the treatment.