Pituitary tumors are relatively common, with reported prevalence rates ranging from 10% to 22% and accounting for 10% to 15% of all intracranial tumors. 3,5,22 With the advent of neuroimaging, the incidental finding of pituitary adenoma has become much more frequent. Chronic headache is a common reason for undergoing neuroimaging. The incidence of headache in patients with pituitary adenomas has been reported to range between 33% and 72%. 1,6,23 The existence of any clear relationship between headaches, pituitary tumors, and surgical treatment of pituitary tumors remains to be elucidated. Chronic headache in patients with pituitary tumors may arise from several putative mechanisms, including tumor volume and its relationship with the sellar structures, functional disturbance within the hypothalamopituitary axis, patient predisposition, and family history. 8,9 Invasion of the cavernous sinus is a proposed etiology of headache given that the sinus contains the ophthalmic branch of obJective The relationship between headaches, pituitary adenomas, and surgical treatment of pituitary adenomas remains unclear. The authors assessed the severity and predictors of self-reported headaches in patients referred for surgery of pituitary adenomas and evaluated the impact of endoscopic transsphenoidal surgery on headache severity and quality of life (QOL). methods In this prospective study, 79 patients with pituitary adenomas underwent endoscopic transsphenoidal resection and completed the Headache Impact Test (HIT-6) and the 36-Item Short Form Health Survey (SF-36) QOL questionnaire preoperatively and at 6 weeks and 6 months postoperatively. results Preoperatively, 49.4% of patients had mild headache severity, 13.9% had moderate severity, 13.9% had substantial severity, and 22.8% had intense severity. Younger age and hormone-producing tumors predisposed greater headache severity, while tumor volume, suprasellar extension, chiasmal compression, and cavernous sinus invasion of the pituitary tumors did not. Preoperative headache severity was found to be significantly associated with reduced scores across all SF-36 QOL dimensions and most significantly associated with mental health. By 6 months postoperatively, headache severity was reduced in a significant proportion of patients. Of the 40 patients with headaches causing an impact on daily living (moderate, substantial, or intense headache), 70% had improvement of at least 1 category on HIT-6 by 6 months postoperatively, while headache worsened in 7.6% of patients. The best predictors of headache response to surgery included younger age, poor preoperative SF-36 mental health score, and hormone-producing microadenoma. coNclusioNs The results of this study confirm that surgery can significantly improve headaches in patients with pituitary adenomas by 6 months postoperatively, particularly in younger patients whose preoperative QOL is impacted. A larger multicenter study is underway to evaluate the long-term effect of surgery on headaches in this patient group.