This study was conducted to identify the alterations of physical properties of elderly persons in Special nursing homes for the aged. The body weight and body mass index(BMI) were measured. Body fat percentage was also obtained by using infrared interactance method. These parameters were measured at the time of the subjects admittance to the facility and during a period of eight months stay in the facility. The results obtained are as follows. BMI and body fat percentage of elderly women who have just been institutionalized in the special nursing homes for the aged were significantly lower than those of the elderly women who have recieved day-care service. Body fat percentage significantly increased after entering the facility, however, both BMI and body weight remained unchanged during the eight months. Lower-body-fat-percentage-elderly were two out of ten, however, those were increased to the normal range at the time of one month after entering in the facility. A definite correlation was obtained between body fat percentage and BMI in elderly who were given day-care service, but the correlation was not obtained between BMI and body fat percentage in elderly who were recently institutionalized in special nursing homes for the aged. These results showed that insufficient nutritional intake at their homes might be improved upon at the special nursing homes for the aged, and pointed out that special nursing homes for the aged had an improving effect on diets for the elderly. Persons of high-body-fat-percentage with low or normal BMI gradually increased after they entered the special nursing homes for the elderly. Moreover, energy expenditure resulting from exercise in special nursing homes for the aged was 0.5-32.5 Kcal/day. A negative correlation was obtained between body fat percentage and energy expenditure due to exercise. It is suggested that a cause of the increase in persons with a high-body-fat-percentage and low or normal BMI may be related to low energy expenditure due to exercise programs in special nursing homes for the aged.