Japan is experiencing an increase in the number of patients with dementia, and the incidence of epilepsy is high among the elderly. A survey of patients with epilepsy who were admitted to our hospital's neurology department showed that new onset epilepsy occurred more frequently in elderly patients. In addition, a greater proportion of elderly patients had dementia as an underlying disease. Although the prevalence of epilepsy in dementia varies, higher brain dysfunctions are known to be related to epilepsy. Because a symptom of epilepsy may be mistaken for dementia, it is important to understand the association between epilepsy and dementia, including their tendencies and characteristics.