Bartter's Syndrome is characterized by the impairment of chloride reabsorbtion in the distal tubules of the kidney. As a result, the kidney loses chloride and persistent hypokalemia, hypochloremia and metabolic alkalosis ensue. Most cases come to the attention of the pediatrican for the early failure to thrive observed in childhood. Its mode of inheritance is thought to be autosomal dominant. in the 1. 5 month old male infant, who admitted to our clinic with the complaints of failure to suck and gain weight, we detected an increase in renal excretion of sodium, potassium and chloride. Plasma renin activity and plasma aldosteron levels were also high. With these results we diagnosed the case as Bartter's Syndrome. We treated the patient with oral potassium and rectal indomethacin. With this therapy, the patient's clinical status and laboratory results improved.