Objective: results of enndoscopic third ventriculostomy (ETV) of non-communicating hydrocephalus. Methods: This is prospective study on 225 patients with non-communicating hydrocephalus underwent operation from 6/2005 to 12/2011. All the patient was have neurological examination, CT Scan and MR!. The third ventriculostomy was done by the head of 300 scope. The outcome at discharge and 6 months later. The complication included death, infection, CSF leakage, hemorrhage or hematoma. Treatment of complications were surgery, VP shunt. Results: The ETV was successful in 204 patients (90,67 percent), and unsuccessful in 21 (9,33 percent). There was 2 deaths (0,89 percent). The VP shunt was done in 19 failured patients (8,44 percent). The complications were founded In 11 patients (4,89 percent). In the group adult patients (more than !5 years olds), ETV was successful in 92,30 percent and was successful in 85,71 percent in the group under 15 year olds (significant with p 0,05). Conclusion: The ETV was safe and effective treatment of non-communicating hydrocephalus.