Endoscopic third-ventriculostomy (ETV) became the treatment of choice for non-communicating hydrocephalus and its effectiveness is largely reported. On the contrary, specific articles on complications and failures of this technique are very rare and this review aims at supplying further information about it. Therefore, an analysis of the main and up-to-date series is made and exhaustive data about complications and failures of ETV and about their incidence are obtained. The overall frequency rate of complications is 6-20%. Their severity may vary either because of the length of the damage (transient or permanent) or the value of the involved structures (basilar artery, areas of the CNS, hypothalamus) or the importance of the injury (from subclinical sequelae to fatal complications). Moreover, this study showed both the risk that the endoscopic procedure must be suspended (intra-operative failure) and the risk of an early (before 1 month) or delayed (even some years after the intervention) narrowing of the ventriculostomy. The rate of and the reasons for failure have been analysed and the success of a second ETV has been estimated. The results of this analysis suggest that the children proposed for ETV are carefully selected and meticulously studied during the follow-up.