The auther had studied dental caries and periodontal disease and other important oral disease in the 806nout patient who came to dental Department in N.M.C. during 1974. The obtained results were as follows ; 1) The dental caries experience rate in the out patient of Dental Departanent in N.M.C. was 8202% and the D.M.F. teeth index was 3.3. 2) The decayed teeth index was 2.18 and the missed teeth index was 0.69 and the filled teeth index was 1065. 3) The periodontal disease rate was 82.8% 4) The oral cancer rate was 2%, mandible and maxillary fracture rate was 4%, and trigeminal neuralgia rate was 0.6%.