OBJECTIVE Endoscopic third ventriculostomy combined with choroid plexus cauterization (ETV+CPC) has been adopted by many pediatric neurosurgeons as an alternative to placing shunts in infants with hydrocephalus. However, reported success rates have been highly variable, which may be secondary to patient selection, operative technique, and/or surgeon training. The objective of this prospective multicenter cohort study was to identify independent patient selection, operative technique, or surgical training predictors of ETV+CPC success in infants. METHODS This was a prospective cohort study nested within the Hydrocephalus Clinical Research Network’s (HCRN) Core Data Project (registry). All infants under the age of 2 years who underwent a first ETV+CPC between June 2006 and March 2015 from 8 HCRN centers were included. Each patient had a minimum of 6 months of follow-up unless censored by an ETV+CPC failure. Patient and operative risk factors of failure were examined, as well as formal ETV+CPC training, which was defined as traveling to and working with the experienced surgeons at CURE Children’s Hospital of Uganda. ETV+CPC failure was defined as the need for repeat ETV, shunting, or death. RESULTS The study contained 191 patients with a primary ETV+CPC conducted by 17 pediatric neurosurgeons within the HCRN. Infants under 6 months corrected age at the time of ETV+CPC represented 79% of the cohort. Myelomeningocele (26%), intraventricular hemorrhage associated with prematurity (24%), and aqueductal stenosis (17%) were the most common etiologies. A total of 115 (60%) of the ETV+CPCs were conducted by surgeons after formal training. Overall, ETV+CPC was successful in 48%, 46%, and 45% of infants at 6 months, 1 year, and 18 months, respectively. Young age (< 1 month) (adjusted hazard ratio [aHR] 1.9, 95% CI 1.0–3.6) and an etiology of post–intraventricular hemorrhage secondary to prematurity (aHR 2.0, 95% CI 1.1–3.6) were the only two independent predictors of ETV+CPC failure. Specific subgroups of ages within etiology categories were identified as having higher ETV+CPC success rates. Although training led to more frequent use of the flexible scope (p < 0.001) and higher rates of complete (> 90%) CPC (p < 0.001), training itself was not independently associated (aHR 1.1, 95% CI 0.7–1.8; p = 0.63) with ETV+CPC success. CONCLUSIONS This is the largest prospective multicenter North American study to date examining ETV+CPC. Formal ETV+CPC training was not found to be associated with improved procedure outcomes. Specific subgroups of ages within specific hydrocephalus etiologies were identified that may preferentially benefit from ETV+CPC.