Bartter syndrome is an autosomal recessive disorder manifested by a defect in 
sodium-potassium-chloride transport in the thick ascending limb of Henle with 
different genetic origins and molecular pathophysiology. Bartter syndrome 
usually a common disease in children and in early infancy presented with 
persistent polyuria and associated with dehydration, electrolyte imbalance, and 
failure to thrive. Though prompt diagnosis and proper treatment of Bartter 
syndrome may improve the outcome, some children will progress to renal failure. 
We report a case of a 6 days-old male infant who was admitted in Neonatal 
Intensive Care Unit, Bangabandhu Sheikh Mujib Medical University, Dhaka, 
Bangladesh on 26 April 2018 for prematurity and low birth weight. On subsequent 
follow up he developed electrolyte imbalance and failure to thrive. Laboratory 
studies revealed hyponatremia, hypochloremic metabolic alkalosis with severe 
hypokalemia. When excessive chloride losses appear to be renal in origin and the 
patient has normal blood pressure and high levels of serum renin and aldosterone 
were considered as Bartter syndrome. Molecular genetic studies are indicated to 
identify the primary genetic defect.