ABSTRACT
Selective hypoaldosteronism is a rare cause of life-threatening salt wasting in the neonatal period. Patients are most frequently diagnosed with the clinical signs of aldosterone deficiency during the first week of life. In this case report, twin premature newborns who were diagnosed with different clinical presentations with hyperkalemia and hyponatremia in the first and 5th months of life are presented. The electrolyte values of the twin cases diagnosed to have selective hypoaldosteronism improved rapidly after administration of oral salt (NaCl) and fludrocortisone treatments. It should be kept in mind that selective hypoaldosteronism should be considered in the differential diagnosis of salt-losing pathologies in the neonatal period, and patients may present with different clinical findings in the first month of life.