Steroids are still widely prescribed in pituitary trans-sphenoidal surgery (TSA). Pituitary-adrenal/thyroid/gonadal functions were prospectively evaluated in 72 consecutive NFPA pts (2087 years, 37 M) before and after endoscopic-TSA (E-TSA) (63 at first operation, 9 at re-operation). All had macroadenoma with suprasellar extension: impinging optic chiasma in 28, extending into cavernous sinus (CS) in 23, giant in 12. Hydrocortisone was infused peri-operatively only in pts with pre-op 0800 am cortisol (F) <8 μg/dl (arbitrary cut-off). After E-TSA clinical picture, F, electrolytes, FT4 and diabetes insipidus (DI) were checked at 13 days, testosterone in M or menses/FSH in women at 1 month, ACTH 1 μg-induced F peak (F-ACTH) and MRI at 3 months. A wide resection (>90%) was performed in all pts, up to empty sella in 60%. Post-op follow-up lasted 111 years (median 5) and regrowth occurred in 5 points with CS invasion. The greater the adenoma size, the worse the pre-op and post-op pituitary function. Central hypogonadism (HypoG) and hypothyroidism (HypoT) were detected in 80.5% and 40.3% before and in 77.8% and 47.2% of pts after E-TSA. Permanent DI occurred in 13.9%. F was 11.4±3.9 before and 11.5±4.3 μg/dl after E-TSA. Pre-op hypocortisolism (HypoA) did not change in 14 points (19.4%, all had also hypoT and hypoG), and was detected in 6 (10.3% of those with previously normal adrenal function) at the first post-op control. No patient whose pre-op F was >8 μg/dl failed, and no patient but 1 whose pre-op F was <8 μg/dl achieved the required 18 μg/dl F-ACTH cut-off. In conclusion, pituitary-adrenal function is usually preserved in NFPA, and only seldom is impaired after complete tumor removal by E-TSA; the first 13 day post-op control reveals the few cases impaired by E-TSA. We recommend peri-operative steroid treatment only In pts with pre-op subnormal F levels, and to evaluate clinical picture and morning F on post-op day 13 for guidance about replacement treatment.