Ubiquitin-positive intraneuronal inclusions were found in the extramotor cortices of ten presenile dementia patients with motor neuron disease. There were inclusions in the hippocampal granular cells and in the small neurons of the superficial layers of the temporal and frontal cortices. Bunina bodies were present in the anterior horn cells in all cases. These results suggest that ubiquitin-related cytoskeletal abnormalities are common in cerebral non-motor small neurons in these patients.