Five hundred twenty-one patients with pulmonary tuberculosis were diagnosed in our three affiliated hospitals during past 10 years. Among them, 43 cases (22 men and 21 women; mean age 54.8 years) who were detected by active case-finding were clinically evaluated. Most of them were detected in an annual mass screening examination, but seven cases were found by contacts examination which was performed on subjects who were contacted with newly diagnosed patients with pulmonary tuberculosis. Fifteen of them were socially jobless on admission. Eighteen cases (41.9%) had underlying diseases, and gastrointestinal diseases and diabetes mellitus were most frequently observed. The final diagnosis was confirmed through bronchoscopic specimens in 18 cases in which Mycobacterium tuberculosis could not be detected from the sputum. Regarding radiological findings according to the criteria of the Japanese Society of Tuberculosis, most cases had unilateral distribution, and were classified as type III (active, non-cavitary) for characteristics and 1 (minimal) for the extent of lesions. Treatment using combination therapy with four drugs including pyrazinamide was performed for over half of these cases and subsequently the clinical efficacy was good except in one case who died due to worsening of the underlying disease. Anti-tuberculous drugs were generally administered to cases suspected of having pulmonary tuberculosis on chest X-ray. However, early diagnosis using bronchoscopy and early treatment seems to be useful, when Mycobacterium tuberculosis is not detected in the sputum.