A man of 61 died after an illness of 20 years duration. The clinical picture displayed progressive dementia, loss of memory, apathy, inertia, emotional lability, temporal and local disorientation, visual hallucination and apraxia. Neuropathological findings predominated in the thalamus and displayed extensive nerve cell loss and gliosis in the anterior, medial, and posterior formations, whereas the lateral formations were somewhat better preserved. The lateral amygdala were severely affected. The cortex showed widespread moderate damage in the third or fourth layer which are interpreted as transneuronal degeneration. In addition moderate atrophy of the vestibular nuclei, the inferior olives and the cerebellum was noted. This case seems to be one of the very rare examples of isolated thalamic degeneration according to Martin (1975).