Among 941 patients of AMI admitted in the period from Jan 1969 to Jan 1989, 89 cases were complicated with diabetes mellitus (9.5%). The diabetic patients are older than non-diabetic, the occurrence of reinfarction and complications during AMI were more frequent and the mortality was higher incidence of complication of hypertension (69.7%) and hyperlipi-demia(39.3%).The clinical characteristics of AMI in diabetic patients are: higher occurrence of silent myo-cardial infarction and more frequent occurrence of heart failure. Recently, evidences from clinic-pathologic and epidemiologic investigations and experimental studies suggest that diabetes mellitus is associated not only with severe coronary atherosclerosis, but also microangiopathy, disorders in vegetative nervous system, and pathology of the myocardium. Therefore effective measures for prevention and treatment of diabetes is very important to decrease the mortality of AMI.