We report a 68-year-old man with progressive speech disturbance and dementia. He was well until 1995, when he noted an onset of difficulty in speech. He was able to name simple objects and understand language, however, he showed great difficulty in spontaneous speech. In 1998, he visited our service. He was alert and oriented, but he showed moderate degree of dementia. He did not appear to have aphasia but he showed marked dysarthria and slurred speech. He showed limb-kinetic apraxia in his right hand. He showed moderate restriction in his vertical gaze, masked face, and dysphagia. He walked normally. No rigidity, ataxia, or abnormal involuntary movement was noted. He showed grasp response and he was bradykinetic. He was treated with levodopa without effect. His condition deteriorated slowly and he was admitted to our service because of fever on February 13, 1999. He was alert but almost mute. He was unable to look upward or downward. Oculocephalic response was preserved. Axial rigidity was noted but no limb rigidity was present. He walked with small steps. Retropulsion was present. Deep tendon reflexes were diminished and the plantar response was flexor bilaterally. Laboratory examinations were unremarkable and his fever went down within a few days by supportive treatment. He was discharged to his home, where his condition deteriorated further. He developed cardiopulmonary arrest on May 3, 1999 and was brought into ER again. Cardiopulmonary resuscitation was unsuccessful and he was pronounced dead at 7:30 in the morning on the same day. The patient was discussed in a neurological CPC. The chief discussant arrived at the conclusion that this patient had corticobasal degeneration. But he felt that the differential diagnosis from atypical progressive supranuclear palsy, in which cortical pathology and symptoms predominated as in corticobasal degeneration, would be extremely difficult. Most of the participants felt that this patient had corticobasal degeneration, but a few thought that he had atypical PSP. Post-mortem examination revealed asymmetric cortical atrophy, which was accentuated in the left motor cortical area. Microscopic examination of the precentral cortex revealed neuronal loss and gliosis. Ballooned neurons and astrocytic plaques were also seen. The substantia nigra showed marked neuronal loss. Neuropil threads were observed in the nigra. Those threads were positive for anti-tau immunohistochemistry. The internal segment of the globus pallidus, the subthalamic nucleus, and the cerebellar dentate nucleus showed mild to moderate neuronal loss. A few neurofibrillary tangle-positive neurons were seen in these structures. Neuropil threads were also seen throughout. Pathologic changes were consistent with the diagnosis of corticobasal degeneration. One of the participants pointed out that he was able to walk at the time when he was showing marked speech disturbance and limb-kinetic apraxia, which was rather unusual for PSP suggesting corticobasal degeneration.