Background: In addition to symptoms of raised ICP, adults with obstructive hydrocephalus often present with cognitive dysfunction. We previously reported the improvement of global cognition at 3 and 12 months following primary adult ETV using the Montreal Cognitive Assessment (MoCA). This abstract presents multidomain cognitive testing using the RBANS. Methods: Obstructive hydrocephalus was identified based on tri-ventriculomegaly on MRI findings with a site of obstruction. Cognitive function was measured using the RBANS and MoCA at two timepoints: pre-ETV and post-ETV. Within patient analysis was conducted using the Wilcoxon Signed Rank Test. Results: Nine adults underwent ETV, 7 primary and 2 secondary (ETV after shunt malfunction), and completed follow-up assessment. Mean age was 33 years old and 7 (78%) were female. Etiology: 3 (33%) congenital and 6 (67%) acquired. Mean follow-up time was 4.5 months. The RBANS total scaled score, attention, and delayed memory index scores were significantly improved post-ETV (p < 0.05). Immediate memory, language, and visuospatial index scores were not significantly different. Secondary analysis shows that picture naming and figure recall subtests were significantly improved. MoCA total scores were not significantly different. Conclusions: ETV in adults with obstructive hydrocephalus results in improvements in global cognition, attention, and delayed memory on RBANS testing.