As a result of the growing proportion of drivers aged 65 years and older, it is estimated that the number of elderly drivers with dementia is increasing in Japan. Since June 2002, if a driver is found to be "demented", his/her driving license shall be revoked in Japan. However, there are no consensus guidelines for demented drivers. Between September 1995 and September 2001, we evaluated 30 drivers with dementia (19 males and 11 females, mean age of 69.4 years) in out patients clinic of the Kochi Medical School Hospital and related hospitals. Clinical Diagnosis was Alzheimer's disease in 20, vascular dementia in 3, mixed type dementia in 2, frontotemporal lobar degeneration in 4, other type dementia in 1. We analyzed their driving behavior and family's attitude. Seventy-three point three percent of 30 drivers with dementia continued to drive after diagnosis. In follow-up periods, number of drivers continuing driving was decreased to 13 (43.3%), while six drivers (27.3%) had a traffic accident or violation. Our study suggests that several important medical and social factors should be considered for the management of drivers with dementia. A consensus medical guideline for demented drivers has to be established.