OBJECTIVE: We investigated whether the use of antihypertensive medication (AHM) is associated with in vivo Alzheimer's Disease (AD) pathologies in older adults with hypertension and examined if the effect differs by drug-class and blood-brain barrier (BBB) permeability of the drug. METHODS: This cross-sectional study recruited participants from the Korean Brain Aging Study for the Early Diagnosis and Prevention of Alzheimer's Disease. Participants comprised both cognitively normal and impaired older adults diagnosed with hypertension (n = 408). All participants underwent comprehensive clinical assessment and [ RESULTS: The AHM group (n = 227) exhibited significantly lower Aβ deposition (B [SE] = -0.104 [0.037], p = 0.006) compared to the non-AHM group (n = 181), even after controlling for age, sex, apolipoprotein E ε4-positivity, vascular risk factors, and mean arterial blood pressure. Further analysis by AHM class showed an association between the use of renin-angiotensin system inhibitors (RASi) and less Aβ deposition (B [SE] = -0.143[0.049], p = 0.004). No significant relationships were observed between the use of BBB-permeable AHM and Aβ deposition. Additionally, associations between AHM use and tau deposition did not reach statistical significance. INTERPRETATION: Our findings suggest that AHM use may be associated with lower Aβ burden in older adults with hypertension. Further studies exploring the underlying mechanism, particularly related to RASi, may provide insights into new therapeutic targets for AD. ANN NEUROL 2025.