We studied the clinical features of culture-positive, previously untreated patients with pulmonary tuberculosis (77 in females and 200 in males), with special reference on the gender differences in clinical features. The mean age was 50.8 y.o. for female and 54.4 y.o. for male, and the age distribution was almost similar to that of newly-registered patients of whole Japan in 1993, namely, small peak in 20s decade and large peaks in the age group over 50 in female, and gradual increase up to 50 years and get to plateau in male. Thirty-nine % in female and fifty-four % in male had various past histories and/or complications which might affect to the deterioration of tuberculosis, such as diabetes mellitus, liver function distress, respiratory failure, malignancy, stomach resection and so on. The rates with each complication were, in general, higher in male than in female. The positive rate to Mantoux reaction was higher in female than in male, and stronger reactions were observed in female than in male. According to the classification of pulmonary tuberculosis designed by the Japanese Society for Tuberculosis (GAKKAI classification), the site(s) of affected lung, the stage and the extent of lesions were more advanced in male than in female, and the positive rate and the amount of bacilli on smear were higher in male than in female. The most marked difference was the location of the main lesions, 80% in the apical and posterior segments of upper lobe (S1,2) and 8% in the superior segments of lower lobe (S6) in male, while 60% in S1,2 and 25% in S6 in female. The rate of complete resistance against to anti-tuberculosis agents was higher in male than in female, but the combination chemotherapy of isoniasid and refampicin with streptomycin or ethambutol was almost equally effective both in males and females, and almost all patients converted to bacilli negative within three months after the initiation of the chemotherapy, except in a few male patients.