We report here an autopsy case of sporadic Creutzfeldt-Jakob disease (CJD) without hereditary burden and with a clinical course typical of sporadic CJD. A 77-year old man developed memory disturbance, followed by gait disturbance and myoclonus. He died of bronchopneumonia 5 months after the disease onset. Post-mortem examination revealed neuronal loss, astrocytosis, and patchy spongiosis in the cerebral cortex and lenticular nuclei. Synaptic-type deposits of prion protein were present in the cerebral cortex. Additionally, Lewy bodies were observed in the cerebral cortex and substantia nigra. Furthermore, senile plaques compatible with definite Alzheimer's disease according to Consortium to Establish a Registry for Alzheimer's disease criteria and neurofibrillary changes of the limbic system consistent with Braak stage IV were found. Based on a review of the published literature, this autopsy case is very rare, and we suppose that the incidence of CJD accompanied by Lewy body disease and Alzheimer's disease is very low.