Objectives: In the present paper we report and discuss our experience with endoscopic third ventriculostomies (ETVs). We will point out surgical, technical data and complications involved. Methods: Between September 1995 and August 2007, we selected 283 patients with hydrocephalus which were submitted exclusively to ETV. Results: In our series, 145 (51.24%) patients were male, and 138 (48.76%) female. Age varied from 2 days to 83 years-old (medium of 15 years and 8 months). Most of the patients hadobstruction at the cerebral aqueduct level (aqueduct stenosis, benign tectal tumors). In our series there was not a single death directly due to the procedure. However 20 patients (7%) evolved with post-surgical complications and 3 of them were permanent, with memory deficit in one and epilepsy in two. There was failure in the procedure during the early post-surgical period in 37 (13%) patients, who then needed ventricular shunt systems to resolve hydrocephalus. Conclusions: Our results suggest that ETV should be considered as the initial treatment to hydrocephalus in all patients whose magnetic resonance exams shows a site of obstruction to the CSF flow. We consider that the most important factor to the treatment success is the adequate selection of patients.