Abstract Background: Prolactinomas account for around 40% to 50% of functional hypophysis adenomas. Over the last 20 years, surgical procedures for pituitary surgery have vastly advanced. For individuals who are resistant or not tolerant to dopaminergic agonists, transsphenoidal surgery is recommend-ed as a second-line therapy. Aim of Study: The purpose of this study is to determine the average time for PRL serum level normalization following transsphenoidal prolactinoma surgery and its relationship to the clinical outcomes. Patients and Methods: This is an observational prospective study of 20 patients with prolactinoma who were treated using an endonasal, endoscopic, transsphenoid approach at Kasr Al-Ainy University Hospitals. All patients underwent a serum PRL level measurement before operation, immediately after-operative, on day one after the operation, the sixth day after the operation, after 3 weeks and 6 weeks later. Results: Twenty patients, 11 men and 9 women, ranging in age from 20 to 60, participated in the study (mean age 36 years). Remission was achieved in 11 patients (55%) along time of study. The surgical complications in our series were CSF leakage in 2 patients, prolonged DI in 2 cases, and one patient with severe postoperative epistaxis. Conclusion: In conclusion, we show here that sequential measurements of prolactin serum level after trans sphenoidal prolactinoma surgery reveal that the time required for normal-ization of PRL serum level ranges from day one after the operation to more than 1.5 months, with an average of six weeks. And that needed time is decreased in the case of macroprolactinoma patients and can reach 24 hours andin-creases in macroprolactinoma patients, which can reach 42 days. Clinical outcomes chronologically are closely related to chemical remission in the form of relief or disappearance of manifestations caused by high serum levels of prolactin.