Patient brains with Parkinson's disease or Dementia with Lewy bodies show aggregation of alpha-synuclein in pre-cerebellar brainstem structures. Furthermore, patients exhibit resting tremor, unstable gait and impaired balance which may be associated with cerebellar dysfunction. Therefore, we screened the cerebella of 12 patients with alpha-synucleinopathies for neuropathological changes. Cerebellar nuclei and neighboring white matter displayed numerous aggregates, while lobules were mildly affected. Cerebellar aggregation pathology may suggest a prion-like spread originating from affected precerebellar structures and the high homogeneity between patients with Dementia with Lewy bodies and Parkinson's disease shows that both diseases likely belong to the same neuropathological spectrum. This article is protected by copyright. All rights reserved.