A 58-year-old man recognized hoarseness and dysarthria followed by weakness of the left upper extremity. Examination five months later disclosed dementia which was manifested dominantly by changes in personality and behavior, but also by symptoms of amyotrophic lateral sclerosis. He became progressively weak, and his neck became rigid and extended for two months. He expired due to respiratory failure at the age of 60. At autopsy, the brain weighed 1120 g with atrophy of the temporal lobes. Microscopic examination revealed marked diminution of Betz cells with astrocytic proliferation in the motor cortex. There was a mild, localized spongy state in the upper layer in the frontal and temporal cortices. There were very few neurofibrillary changes and senile plaques, and no Pick's argentophilic bodies. Fibrillary gliosis was found in the white matter of the temporal lobes, external segment of the globus pallidus and the amygdaloid nucleus. The substantia nigra showed depletion of pigmented cells, free melanin pigment and reactive astrocytosis. A diminished number of motor neurons in the brain stem and spinal cord accompanied astrocytic gliosis, while the remaining cell contained many Bunina bodies. The pyramidal tracts showed mild degeneration bilaterally below the pyramis in the medulla. There are a number of cases in the literature whose pictures consist of amyotrophic lateral sclerosis, dementia and/or extrapyramidal symptoms. This case is identical to those cases. But in this case, the clinical and pathological features of amyotrophic lateral sclerosis are more dominant than in other cases.