Background: Aβ-related angiitis (AβRA) is a rare presentation of cerebral amyloid angiopathy, where vasculitis results from an auto-immune reaction to amyloid deposits in leptomeningeal and cortical vessel walls. Anti-CD20 monoclonal antibodies, such as rituximab, have demonstrated efficacy in systemic small vessel vasculitides, particularly in refractory cases. The efficacy of rituximab in AβRA remains unknown. Methods: Patient chart, functional measures, and laboratory findings were reviewed from the time of patient admission until 12 months after discharge. Results: A 61-year-old man presented with headache and altered mental status. Brain MRI revealed multiple cortical infarcts, leptomeningeal enhancement, and cortical microbleeds, and brain biopsy ultimately confirmed the diagnosis of AβRA. The patient developed new ischemic lesions despite corticosteroid pulse, and intravenous cyclophosphamide was halted after four weeks due to iatrogenic acute hepatitis. Rituximab was initiated and led to sustained clinical improvement with no subsequent relapses. Maintenance therapy involved gradually tapered low-dose oral steroids and rituximab at 6- and 12-months post-induction. Conclusions: This report suggests that rituximab may be effective in inducing remission and preventing relapses in biopsy-proven case of AβRA. Controlled studies are needed to better assess the efficacy and tolerability of anti-CD20 antibodies in cerebral vasculitis.