The advantages of endoscopic transnasal pituitary surgery include a panoramic view of the area and easy reoperation. Based on this, we performed a planned staged operation in two cases of large pituitary adenomas, extending to the suprasellar lesion, using the endoscopic transnasal trans-sphenoidal approach via both nostrils. In the initial operation, a tumour mass was from the intrasellar region, however, that part of it in contact with the tumour capsule was left intact for prevention of peri-operative injury. The residual mass descended into the sellar floor at the second operation, and was easily resected with no complications. A staged operation by the endoscopic transnasal approach, although it requires two operations, is thought to be a safe and efficient procedure for the removal of large pituitary tumours.