Objectives: To preserve olfactory function in each nostril following pituitary surgery is important in the long term. However, no reports evaluating olfactory outcomes in individual nasal cavities following endoscopic endonasal transsphenoidal approach (EETSA) for pituitary surgery have been published. Here, we used an endoscopic modified transseptal bi-nostril approach for pituitary surgery, with possible olfaction preservation without turbinate resection, and evaluated olfactory outcomes in both left and right nostrils.