The endoscopic third ventriculostomy (ETV) is a neuroendoscopical procedure that represents a more suitable alternative to the extracranial shunting in obstructive hydrocephalus. It consists of fenestrating the floor of the third ventricle and thus establishing a free flow of the cerebrospinal fluid from the ventricles to the site of resorption in the subarachnoid space. It offers a more physiological solution and a chance at a shunt-free life for patients with hydrocephalus. The main indication for the procedure is obstructive hydrocephalus, however, it can also be useful in patients with other forms of hydrocephalus. Case Summary: We present a treatment flow of a 20-year-old patient, diagnosed with an obstructive hydrocephalus due to supratentorial obstructing ventriculomegaly due to an intraventricular lesion that was successfully treated with an ETV. Keywords: Endoscopic third ventriculostomy, Obstructive hydrocephalus, Aqueductal stenosis