Neonatal Bartter syndrome is a rare condition resulting in defective absorption of sodium and chloride in the thick ascending loop of Henle resulting in excessive loss of urinary electrolytes and fluid. Delayed diagnosis can result in severe dehydration with increased morbidity and mortality. High index of suspicion is necessary as typical biochemical changes with hypokalaemic hypochloraemic metabolic alkalosis may not be present early on especially with the presence of dehydration and infection.