Hyperparathyroidism during pregnancy is associated with greatly increased perinatal morbidity and mortality. Severe neonatal hypocalcemia and tetany is a particularly serious complication. Surgical removal of the abnormal parathyroid glands is currently recommended during pregnancy in view of the severity of the complications in the untreated patients and the favorable results in patients who have had surgery during pregnancy. Two patients are reported in whom surgery during pregnancy could not be performed. They were treated with oral phosphate, which successfully decreased serum calcium; their infants remained normocalcemic throughout the neonatal period. It is suggested that in selected cases medical treatment with oral phosphate can be an effective therapeutic alternative and surgery may be postponed until after delivery.