Idiopathic normal pressure hydrocephalus (iNPH) is an important cause of gait disturbance, cognitive impairment and urinary symptoms in elderly adults that may resemble other disorders among elderly such as Parkinson's and Alzheimer's disease but have specific neuroradiological features. Population-based epidemiological studies carried out recently in Japan and Sweden demonstrated the prevalence of possible iNPH was around 2 % in the elderly population. Two independent committees of experts, American-European and Japanese, have come up with diagnostic guidelines, which improve management of patients and facilitate clinical studies of iNPH. Specifically, the Japanese guidelines stressed the diagnostic importance of Disproportionately Enlarged Subarachnoid Space Hydrocephalus (DESH) on diagnostic images. Recent a number of studies confirmed that DESH is predictive of clinical improvement after CSF shunting. As for treatment of iNPH, the only effective treatment is CSF diversion with shunt surgery. Several prospective cohort studies demonstrated benefits of ventriculo-peritonal (VP) shunt. SINPHONI-2, a randomized controlled trial comparing lumbar subarachnoid space-peritoneal (LP) shunt to conservative therapy, clearly demonstrated benefits of LP shunt. It is essential to identify patients with iNPH as 70–80% improve by CSF shunting. However, patients with iNPH are often misdiagnosed and inadequately treated. There seems even negativism against iNPH and CSF shunting among neurologists. We neurologists should be concerned actively more than ever with management of patients with iNPH and research of iNPH.