A 53-year-old man with an aggressive T-cell lymphoma was found at autopsy to have severe cerebellar degeneration, presumably as a 'remote' effect of malignancy. The degree of cerebellar atrophy was unusually pronounced and widespread, involving both Purkinje cell and granule cell layers, although patches of preserved and essentially normal cerebellar cortex were identified. This case is of particular interest in view of data which indicate that cerebellar Purkinje cells and T-lymphocytes share antigenic surface markers.