Objective : The endocrine dysfunction after the operation for suprasellar arachnoid cysts is not rare. The careful operation to prevent structures can prevent this complication, but it is not enough and effective to prevent it. Authors present technical surgical considerations to prevent this complication with a review of our suprasellar arachnoid cyst patients who had postoperative endocrine dysfunction. Methods : From January 2002 to December 2009, eight patients who had suprasellar arachnoid cysts with visual impairment underwent surgery. The mean age was 57.1 years (range, 33-77). Preoperatively, their endocrine function was clinically normal, and laboratory hormonal levels were within normal ranges. Cyst fenestration was performed by craniotomy (n=6) or by a neuro-endoscopic procedure (n=2), and, simultaneously, along with a cyst wall biopsy. Results : The surgery was uneventful in all eight patients, and there were no neurological morbidities. However, in four patients, endocrine dysfunction occurred postoperatively. We compared these four patients (group A) to the other 4 patients without endocrine dysfunction (group B) with intraoperative findings and with the histopathological findings of the cyst wall biopsy. The group A patients had more abundant vasculature on the cystic wall than the group B patients according to both the intraoperative findings and the histopathological findings. Conclusion : When performing a surgical cyst wall fenestration, surgeons should try to minimize the destruction of the cystic wall vasculature and not to make the fenestration at a site that contains many vascular striae.