A 67-year-old woman was admitted to our hospital with progressive aphasia. There was no family history of similar diseases or any history of dura transplantation. Cranial magnetic resonance imaging (MRI) showed high signal areas in the temporal and parietal cortex predominantly on the left side on both T2-weighted images and on diffusion-weighted images. There were no periodic synchronous discharges observed on the electroencephalogram. As prion protein gene codon 180 point mutation (Val/Ile) was detected, we diagnosed her as having Creutzfeldt-Jakob disease (CJD). The characteristics of CJD of this type differ from those of sporadic CJD. To date, few papers on CJD with point mutation of codon 180 have been reported from Japan.