A family in which three of four children are affected with Bartter's syndrome is described. The three affected sibs had hypokalemia and persistent urinary potassium loss. Two also were hyponatremic despite hyperaldosteronism. Because of the persistent urinary potassium loss, thought to be due in part to the hyperaldosteronism, a total adrenalectomy was performed in one affected child. His urinary potassium loss was not affected by this procedure. It was concluded that adrenalectomy should not be performed in these patients and that the hypokalemia is not due to the hyperaldosteronism. It is possible that the primary defect is in renal reabsorption of both sodium and potassium.