0ne huridred and seventy-one patients with pulmonary tubercuIosis were found in 1,065 patients with diabetes who were diagnosed at National Medical Center from Jan. '71 to Dec. '81. We used 100 cases at random in 171 cases. 1) An incidence of patients with puImonary tuberclosis in patients with diabetes mellitus was 16. 1 percent. Male(72 cases) and Female(28 cases) ratio of the patients was 2.6: 1. The highest incidence was seen in the 6th decade, and the next in 5th decade. 2) Far advanced pulmonary tuberculosis was most common on chest roentgenograms. Cavitation was seen in 46 percent of all cases. 3) There was no correlation between initial fasting bIood sugar and extent of pulmonary tuberculosis on chest roentgenograms. 4) The longer the duration of diabetes mellitus, the higher the incidence of pulmonary tuberculosia But, there was no correlation between tbe duration of diabetes mellitus and the extent of pulmonary tuberculosis on chest roentger.ograms. 5) In pulmonary tuberculosis in diabetic patients, the cases of normal renge of WBC was 42% and the cases below the normal range of lymphocyte was 80% of all cases. 6) There was no correlation between control of diabetes mellitua and improvement of pulmonary tubercuIosiis on chest roentgenograma. And the combination of INH, RIF and PZA was most effective, which seemed to be similar in non-diabetic patierits.