Abstract Body: Alzheimer’s Disease (AD) is the most common form of dementia and is characterized by progressive neurodegeneration and cognitive decline. Cardiovascular risk factors in AD lead to decreased cerebral blood flow (CBF), particularly in capillaries, which play a crucial role in the exchange of oxygen and nutrients in response to neuronal activity. Deficits in capillary-level cerebral blood flow are likely to induce vascular inflammation and disrupt the shear forces associated with blood flow, both of which are hallmarks of Alzheimer's disease and aging. The Piezo1 channel has been shown to be a crucial mechanosensor in brain capillaries that mediates mechanically induced endothelial cell Ca²⁺ transients, suggesting a possible role for Piezo1 in CBF regulation. Here, we investigated the contribution of mechanosensitive Piezo1 ion channels to capillary stalling and CBF reductions in the 5xFAD mouse model of AD. We performed cranial window implantation on twelve 4-month-old 5xFAD mice and twelve age-matched wild-type controls. Using in vivo multiphoton imaging, we measured cerebral blood flow and capillary stalling in 5xFAD mice following injection with Yoda1, a Piezo1 agonist, before, 24 hrs and one week after Piezo1 activation. Our findings demonstrated that modulating Piezo1 activity reduced capillary stalling and improved CBF in response to Piezo1 activation. Further, Yoda1 injection for one week improved functional hyperemia, measured using laser speckle contrast imaging, in 7-month-old 5xFAD mice. These results suggest the crucial implication of Piezo1 in vascular dysfunction during AD. Importantly, this work highlights the potential therapeutic targeting of Piezo1 to mitigate the effects of impaired cerebral perfusion in AD.