Background: Bartter syndrome is a rare autosomal recessive inherited salt wasting tubulopathy, it`s incidence proportion is 1.2 cases per 1.000.000 live births. The present case - report discusses a clinical case of an antenatal Bartter syndrome (type II) with a novel mutation and it`s course from antenatal presentation to 6 months postpartum. Case Presentation: The case-report discusses a clinical case of an antenatal Bartter syndrome (type II) with a novel homozygous missense variant mutation in KCNJ1 gene: c.554C>T (p. Pro185Leu). Symptoms presented from 24 weeks of pregnancy as premature labour threats, maternal dyspnoea and severe polyhydramnios (amniotic fluid index 36 cm). Therapeutic interventions included use of indomethacin, dexamethasone, micronized progesterone and three consequent amnioreductions. Pregnancy was prolonged until 32 weeks and induced due to severe reoccurring polyhydramnios, progressing maternal dyspnoea and inability to perform next amnioreduction. Labour was complicated by severe placental abruption and new born – boy was referred to neonatal intensive care unit. Neonatal period was complicated by electrolyte abnormalities: hyponatremia, hypochloremic metabolic alkalosis, transient hyperkalaemia that gradually developed into hypokalaemia, hypercalcemia and elevated rennin and aldosterone levels characteristic to type II Bartter syndrome. At 6 months (corrected age 4 months) he is gaining weight within normal ranges and his psychomotor development is ahead of his corrected age, without any need for daily medications. Conclusion: The present case report describes the clinical course of a Bartter syndrome is of high importance, due to the reason that it shows clinical course of patient with novel mutation and offers one of the ways how to manage the disease. The described novel mutation may have favourable prognosis for neonate. The pregnancy should be managed as high-risk pregnancy with expertise in perinatal diagnostics and interventions. Early recognition, and interventions, are and essential to prolong a pregnancy and lessen prematurity complications.