Abstract: Objective To investigate the surgical procedure and effects of endoscopic endonasal transsphenoidal surgery (EETS) for giant pituitary adenomas. Methods Clinical data about 76 consecutive patients with giant pituitary adenomas who underwent EETS from January 2014 to May 2016 in our hospital were retrospectively analyzed. Of the 76 patients, 40 were male and 36 were female with age ranging from 18 to 72 years (mean age, 47.3 years). There were 64 cases with non-functioning adenomas and 12 cases with hormone-secreting adenomas. The maximum tumor diameter varied from 4.0 to 7.1 cm, with mean diameter of 4.8 cm. Postoperative MRI and endocrine function were re-examined routinely to evaluate the therapeutic efficacy. Results Total removal of the tumor was achieved in 32 cases (42.1%), 26 patients (34.2%) underwent subtotal resection, and 18 patients (23.7%) underwent partial removal. Factors that limited the degree of resection were a multilobular configuration of the adenoma and cavernous sinus invasion (P< 0.05, respectively). Of the 56 cases with preoperative vision loss, vision improvement achieved in 43 cases (76.8%), unchanged in 10 cases (17.9%), and worsened in 3 cases (5.3%) due to apoplexy of residual tumor. The major postoperative complications included CSF leak in 12 cases, permanent diabetes insipidus in 7 cases. During a mean follow-up of 14.5 months (range 2-32 months) in 52 cases, 83.9% of the cases went back to daily life and work and 4 cases (6.4%) suffered recurrence. Conclusion Endoscopic endonasal transsphenoidal surgery provides effective management of giant pituitary adenomas with favorable results. Adjuvant therapies including medical and radiation therapies offer the chances to control the residual tumors after the maximal surgical removal of giant adenomas.