90 Cases of diabetics who came to department of internal medicine and dental clinic, National Medical Center, and 90 Cases of patients who came to dental clinic without general symptom were examined with oral examination and intra-oral x-ray study, from May, 1975 to Oct. , 1975. The obtained results were as follow : In the diabetics, gingval inflammaory changes, alveolar bone resorption and tiih mobility were more severe than nondiabetics who had similar local initants in the oral cavities.