Dementia a syndrome of acquired intellectual deterioration, is an etiologically  nonspecific condition that can be permanent or reversible. Potentially reversible conditions may be identified in approximately 15% of patients referred for diagnostic evaluation of dementia. The most frequently observed conditions are depression, drugs metabolic disturbances, space-occupying lesions, and normal pressure hydrocephalus. The neurosurgical conditions that can be produce a reversible dementia syndrome are normal pressure hydrocephalus, subdural hematomas, intracranial tumors and cerebrovascular lesions. Coexistence of dementia and focal neurologic deficit usually  indicate  intracranial mass  lesions . If normal pressure  hydrocephalus is present, gait disturbance and incontinence is able to associated with dementia. The author briefly reviewed characteristic of the dementia in neurosurgical field based on author’s experience and some articles related to the dementia