Introduction:In pediatric hydrocephalusit is not clear whether treatment with endoscopic third ventriculostomy (ETV) versus shunt results in improved health status and quality of life (QOL). To study this, the International Infant Hydrocephalus Study (IIHS) was started in 2005 as a prospective, multicentre study to compare ETV and shunt in infants (<24 months old) .Herein, we present the 5 year primary outcome results. Methods: Patients received ETV or shunt, based on either randomization or parental preference. Outcome  measures at 5 years of age, were the Health Utilities Index Mark 2 (HUI-2) (primary outcome) and the Hydrocephalus Outcome Questionnaire (HOQ), a measure of QOL. Results were compared in an analysis of covariance, adjusting for baseline variables including age at surgery and baseline development status. The trial was registered at clinicaltrials.gov (NCT00652470). Results: 78 children (19 treated with shunt, 61 treated with ETV), were assessed at a mean age of 62.1 months (SD 6.3).  The mean 5 year HUI-2 utility score was 0.90 (SD 0.19) for ETV and 0.94 (SD 0.10) for shunt (p=0.21). The mean 5 year HOQ Overall score was 0.81 (SD 0.15) for ETV and 0.85 (SD 0.12) for shunt (p=0.42). Similarly, no significant differences were noted between the HOQ subscores (Cognitive, Social-Emotional, Physical) or developmental measures at 1, 2, and 3 years. Conclusions: The overall health status and quality of life in this cohort of infants treated for aqueductal stenosis is high, with no significant difference between those treated initially with ETV or shunt.