Zaccaria V, Bacigalupo I, Gervasi G, et al. - Researchers conducted this systematic review to obtain all available studies reporting prevalence and incidence rates of idiopathic normal pressure hydrocephalus (iNPH) and to evaluate their methodological quality and consistency. Published up to June 2019, all available studies were retrieved exploring the databases PubMed, ISI Web of Science, and the Cochrane Database of Systematic Reviews. Searches from bibliographies and other sources yielded 659 records. In total, 28 studies were selected and applied the predefined inclusion and exclusion criteria. The high methodological and clinical heterogeneity of the included studies does not allow appropriate conclusions to be drawn about the iNPH epidemiology. In addition, high-quality, population-based studies should be conducted to enable a better understanding of this condition's epidemiology. Furthermore, the implementation of guidelines on the diagnosis and management of iNPH in current clinical practice should also be endorsed.