It has been asserted that per diem payment system should be introduced, in place of the current fee-for-service system, for payment of the inpatient services of the geriatric hospitals, Based on the assentation, this study aims at calculating costs and profits per inpatient-day of the geriatric hospitals, and thereby at contributing to the managerial improvement from the both sides of the Government and the hospitals. Relevant data of the three months, May to August, 2002 were collected from the five geriatric hospitals, and per inpatient-day costs and profits were calculated for the three disease groups. Major results and conclusions are as follow : Firstly, total costs per insured inpatient-day of the geriatric hospitals are 65, 389 won for dementia (including optimal profit of 3,858 won), 69,730 won for stroke (including optimal profit of 4,117 won), and 70,085 won for other diseases (including optimal profit of 4,134 won). Secondly, the amount of the non-insured costs per inpatient-day occupies 34.5% of the total costs for dementia, 30.3% for stroke, and 30.1% for other diseases. Thirdly, the total amount of the per inpatient-day costs calculated including the optimal profits is, on the average, higher by 12% than the present price level calculated for the current fee-far-service system. This implies that the present price level should rise by 12% when the current fee-far-service payment system be maintained, and Finally, introduction of a sliding-scale payment system should be considered for the inpatient medical management fees for the length of stay over six months or more that are being cut in the claim examination process by the insurance corporation.