We reported a 60-year-old woman who suffered from isolated neurosarcodosis. She was presenting comprehensive dysfunction and intermittent high fever. In several months she gradually developed dysorientation, amnesia, dementia. However, no focal sign such as paralysis or sensory disturbance was demonstrated. Her blood chemistry showed normal including ACE (angiotensin converting enzyme) and lysozyme. Cerebrospinal fluid revealed elevated mononuclear cells, protein, and decreased glucose level. At first we treated with antibiotics including antiviral drugs in suspect of the infectious encephalomeningitis. But no improvement was observed. The elevation of ACE in spinal fluid made us suspect of neurosarcoidosis. So intravenous predonizoron (1,000 mg) was given, improving. Her high fever and mental disturbance improved. Second spinal fluid showed improvement. During the course her brain MRI revealed new bilateral diffuse confluent high intensity lesions at the deep white matters. Brain biopsy of deep matter at the right anterior lobe showed noncaseating granuloma. Since systemic work-up to detect sarcoidosis did not reveal lesions other than CNS, we considered this patient as having isolated CNS sarcoidosis.