The classical Bartter syndrome is an uncommon tubular disorder of autosomal recessive inheritance, characterized by early childhood onset of polyuria, polydipsia, vomiting, dehydration, constipation and salt craving habit. The long-term outlook for patients with Bartter syndrome is not certain. If not properly treated, it may lead to failure to thrive and growth retardation. We herein report a case of 18-month-old girl child who presented chronic diarrhea and failure to thrive and then was diagnosed as a case of classical Bartter syndrome. She was successfully treated with potassium supplementation and ibuprofen therapy.