Cortical peri-operative biopsies obtained from 11 idiopathic normal pressure hydrocephalus (iNPH) consenting patients (aged 67-88 years, median 74) were immuno-stained for Beta-amyloid (AMYB), Amyloid Precursor Protein (APP), total Tau, phosphorylated tau (AT8), Alpha Synuclein (AS), TDP- 43, P62 & GFAP. 5/11 patients had AMYB deposits, 2 diffuse plaques only, 3 diffuse and cored plaques; 1 also with amyloid angiopathy (CAA). Plaque neurites were labeled for APP and AT8 in all 3 patients with cored plaques; in one were these and neurofibrillary tangles labeled for total tau. The surface area covered by AMYB ranged from 12.8% to 0.08%. The presence of AMYB correlated with age (t, p=.02). Neither AS nor TDP-43 pathologies were identified. The density of cortical GFAP+ astrocytes showed a trend towards inverse correlation with age (r=-0.58, p=.06) but not with AMYB or AT8 pathologies. There were no significant correlations between pre-shunt Evans Ratio and MoCA scores and presence or amount of pathology. Improvement in ventriculomegaly (5/11) did not differ between patients with and without AMYB pathologies. Improvements in MoCA (6/8) were more common in patients without AMYB deposits (X2,p=.028; t, p=.04), but also in younger patients (t, p=.019). The patient with CAA improved, but the one with total tau pathology did not improve cognitively, although her gait did. In this preliminary study only AD-related pathology was found in iNPH. Cognitive improvement was associated with younger age and absence of amyloid deposits; however, a larger number of patients will be required to dissect these variables.