Objective To discuss the etiology,clinical features and treatments of patients with pituitary adenomas having onset symptom of hyponatremia.Methods Retrospective analysis was performed on etiology,clinical features and treatment methods of 28 patients with pituitary adenomas having onset symptom ofhyponetramia,admitted to our hospital from Jantary 2003 to December 2012.Results Among 28 patients,27 had non-functional pituitary adenomas and one prolactinoma; 23 had pituitary macroadenomas and 5 giant adenomas; 22 achieved total tumor resection through transsphenoidal approach,2 subtotal removal and 4 received conservative therapy.In total,13 were combined with hypocortisolism,8 with hypothyroidism,5 with both hypocortisolism and hypothyroidism,and 2 with hyponatremia caused by syndrome of inappropriate secretion of antidiuretic hormone in preoperative evaluation.Hyponatremia was corrected by hormone replacement therapy and water limitation during perioperative and postoperative period.Conclusions Pituitary adenomas with onset symptom of hyponatremia are mostly non-functional pituitary macroadenomas.Pituitary adenoma resection is the first-line treatment; hyponatremia and anterior pituitary hypofunction should be corrected in perioperative period,and close postoperative follow-up is necessary.