This study is based on five years follow-up study on the aged with dementia who are cared in own home. The purpose of this study is to estimate mortality during five years and to find physical, mental, and social factors which influence on death and diseases in demented people. In 1984, the authors carried out an investigation about the age-related dementia in 14, 984 residents, aged more than 65 years in Tokorozawa City, Tokyo metoropolitan area. In this study 306 persons with dementia and their family members who cared them were interviewed. In 1991, the authors followed up them. 201 cases of them died already during five years, and 81 cases survived and 24 cases were lost in the reasons of moving away and admission into either hospitals or institutions. As the results in Hasegawa's Report (1981), the storongest factors of mortality in the aged with dementia were higher age, severe dementia, low ADL levels such as bedridden status and incontinence. Besides, the authors found different patterns of mortality by age between population of 65-79 years old (at inital survey) and 80 years and over, and by length of time suffering from dementia between less and more than 5 years. There were no typical influences on mortality by differences of care conditions and caregivers.