Transsphenoidal hypophysectomy has generally been performed via the sublabial transseptal approach. We can be free from the disadvantages of the sublabial transseptal approach, such as limitation of exposure from the overhanging upper lip, loss of nasal tip projection and numbness of the upper teeth, if we do the hypophysectomy with the transseptal transsphenoidal approach using columellar flap. And transseptal transsphenoidal hypophysectomy using columellar flap is a rapid, simple method for gaining access to the sphenoid sinus. The authors analyzed 75 patients who had received transseptal transsphenoidal hypophysectomy with columellar flap from August 1989 to August 1992. The following results were obtained : 1) Pituitary adenomas were mostly stage A in 29 cases(39.2%) and grade II in 37 cases (50%) according to Wilson's classification. 2) The majority of types of pneumatization of the sphenoid sinus were postsellar type with 44 cases (58.7%). 3) Among functioning adenomas (53 cases), 22 cases (41.5%) were endocrinologically cured. 13 cases (24.5%) were improved. 4) Postoperative complications induded 12 cases of transient diabetes insipidus (16%), three cases of CSF rhinorrhea (4%), two cases of septal perforation, two cases of panhypopituitarism, two cases of numbness of incisional area, one case of meningitis, one case of sinusitis, and one case of postoperative bleeding.