Endoscopic third ventriculostomy in a case of obstructive hydrocephalus with neurofibromatosis (NF-1) was reported. The patient was a 25-year-old male, who suffered from progressive headache and somnolence. He underwent a ventriculoperitoneal shunt at the age of 11 years. After that, 8 times of shunt revision and unilateral subtemporal decompression were performed during 14 years until this admission. The programmable valve system was used at the last procedure. On admission, computed tomography (CT) scan showed marked enlarged lateral and third ventricles. The patient was diagnosed as hydrocephalus resulting from shunt malfunction. An endoscopic third ventriculostomy was performed and his symptoms improved immediately. The size of the lateral and third ventricles was revealed normal on the CT 18 months after the third ventriculostomy.