Three cases of primary hyperparathyroidism in pregnancy are described. Patient 1 developed left thigh pain and lower abdominal pain at 34 weeks' gestation. Patient 2 had right flank pain and lower abdominal pain at 32 weeks' gestation. Both patients accepted medical therapy initially, which resulted in poor control of hypercalcemia. Patient 1 delayed her parathyroidectomy until the postpartum period; she had maternal hypercalcemia and neonatal hypocalcemia. Patient 2 accepted parathyroidectomy at 32 weeks' gestation with an uneventful outcome for both mother and baby. Patient 3 was asymptomatic; her hyperparathyroidism was diagnosed postpartum after neonatal hypocalcemia and agreed to parathyroidectomy. All 3 patients had a parathyroid adenoma.