We evaluated the ability of transsphenoidal surgery to produce visual improvement, endocrine remission, and complete tumor removal in 113 patients with pituitary adenomas extending beyond the sella turcica. Eighty-one percent of patients with preoperative visual field defects had postoperative improvement, 19% had no change, and none deteriorated significantly. Seventy-nine percent of patients with diminished preoperative visual acuity had postoperative improvement; none deteriorated. Endocrine remission of functioning tumors was achieved in 43% of patients and complete resection by computed tomography scanning was also obtained in 43%. There were no deaths in this series and the major complication was cerebrospinal fluid leak, which occurred in 3% of patients. Comparison with transfrontal surgery suggests that these results are as good as those with transfrontal procedures and that the incidence of serious side effects is considerably lower. Transsphenoidal surgery is safe and effective in the surgical management of large pituitary adenomas.