Background: To know actual conditions and a balance between food intake and energy expenditure of each of the elderly in the super-aged society is very important. Aim: To determine the resting energy expenditure (REE) of the elderly residing in the "Roken". Methods: For Study 1, REEs of 47 elderly people in the Roken were measured. For Study 2, REEs of 22 patients who were admitted to a general hospital were measured. Results: In Study 1, REE of the elderly people in the Roken ranged from 523 to 1,628 kcal/day/body; the mean value was 909 ± 239 kcal/day/body (mean ± SD) and 21.6 ± 4.5 kcal/kg/day. A discrepancy between REE and dietary energy intake was observed. In Study 2, REE of patients in the hospital widely ranged from 589 to 2,549 kcal/day/body; the mean value was 1391 ± 459 kg/day/body (mean ± SD). Conclusions: The mean value of REE of the elderly in the Roken was 74% lower than that of the healthy individuals in previous reports. The observed discrepancy between REE and dietary energy intake suggested the need for improvement in the effective absorption of nutrients from the digestive system, which may be more important than food intake.