Background: Most surgical teams currently consider that endoscopy has become the "gold standard" technique for the transsphenoidal approach to pituitary surgery. Pituitary adenomas are commonly benign tumours and should benefit from the least invasive approach. Method: In Foch Hospital, from 2006 to 2020, 2835 patients with pituitary adenomas were treated with a mononostril endoscopic endonasal approach. Here we describe the fine details of the nasal, sphenoidal and sellar steps of this technique. Conclusion: Complete preservation of the nasal corridor, luxation of the nasal septum and tailored sellar bone resection are essential for safe resection of pituitary adenomas. [ABSTRACT FROM AUTHOR]