The incidence of diabetes mellitus among Koreans as shown an increasing tendency recently, probably due to the various factors such as the improving living conditions. The majority of people are ignorant or indifferent to the nature, progress and prognosis of diabetes mellitus in Korea. 107 cases of diabetes mellitus which had been admitted to Severance Hospital between January and August, 1971 were Studied. Of these 107 cases, 22 cases were interviewed thoroughly during their hospital stay and the response to their diet therapy was carefully checked. 1) Of the 107 cases 69 cases were male and 38 cases were female; the sex ratio was 18:1. The age of the onset of the disease was as follows: 2 cases were under 20 years of age; 20 cases (18.7%) were under 40 years of age and 85 cases (79.5%) were over 40 years of age. Juvenile diabetes was less frequent when compared with developed countries. 2) Patients complaints and symptoms on admission, complications of sickness, and duration of sickness until the female discharge were also studied. We found that the incidence of tuberculosis complication in diabetes melltius was alarming (13. 8%). 3) In most cases, the control of diabetes was inadequate and diet practisis by the patients was also very poor even when they had known of the diabetes mellitus for a considerable period of time. During hospitalization 75 cases (70.0%) were controlled by diet and oral medications alone. Only 16 cases (15.0%) needed insulin injection, the remaining 16 cases required both diet control and insulin injection. 4) In general, patients received hospital diet satisfactorily. Only a few cases complained of difficulties with milk intake because of no previous dietary experience or of excessive meat orfish because they preferred vegetables and fruit. 5) Patients responded well to the dietitians interviews in the hospital but follow up study and care were poorly organized after discharge from the hospital. 6) The diet exchange 1ist published by the Korean Diabetic Association was not well received by the patients or the general puplic because it is not inexpensive and detailed instructions were not given at the time of discharge from the hospital.