Background Idiopathic aqueductal stenosis is a cause of noncommunicating hydrocephalus, which actual treatment with endoscopic third ventriculostomy (ETV) could assess without any interference with the etiology. The results of ETV in this indication therefore could be interpreted as the result of the surgical procedure alone, without any additional factors related to the etiology of the cerebrospinal fluid pathway obstruction, such as hemorrhage, infection, brain malformations, or brain tumors or cysts. Methods After a brief description of pathogenesis of hydrocephalus in aqueductal stenosis, the authors review the literature for studies on ETV, extrapolating patients with idiopathic aqueductal stenosis in infancy, childhood, and adulthood. Differences in outcome between patients treated with ETV and patients treated with ventriculoperitoneal shunt (VPS) are also reviewed. Results The overall success rates of ETV range between 23% to 94%, with a mean of 68%; when only patients affected by obstructive triventricular hydrocephalus secondary to aqueductal stenosis are considered, the success rate is actually quite homogeneous and stable, being above 60% at any age, even if a trend in lower success rate in very young infants (younger than 6 months of age) is noticeable. The few reports on intellectual outcome failed to demonstrate differences between ETV and VPS. Conclusions Several issues, such as the cause of failures in well-selected patients, long-term outcome in infants treated with ETV, effects of persistent ventriculomegaly on neuropsychological developmental, remain unanswered. Larger and more detailed studies are needed.