Cavernous sinus surgery has always been a surgical challenge because of the high functional importance of this region and the associated high morbidity. The augmented peripheral vision of the endoscope has led to the development of surgical approaches that allow adequate exposure of the cavernous sinus, with a reduction in surgical morbidity. Since 1998, 65 patients with pituitary adenomas and intraoperative evidence of cavernous sinus invasion were treated with a purely endoscopic approach. Follow-up was of at least 6 (mean 51.2) months. There was no perioperative mortality and extremely low morbidity. Radical tumor removal was obtained in 21/35 cases with nonfunctioning adenomas. Hormonal remission was obtained in 13/30 functioning adenomas. One patient with partial hypopituitarism and 1 patient with persistent diabetes insipidus were seen. Three patients with delayed CSF leaks required endoscopic repair. In 1 patient with hemorrhagic infarction in a residual tumor, reintervention with craniotomy was necessary. We advocate the central role of surgery in the treatment of cavernous sinus tumors, since it allows definition of true cavernous sinus involvement, histopathological diagnosis and, when cure is not feasible, tumor volume reduction, which might be an important factor in the response to adjuvant therapy.