BACKGROUND: Endobronchial tuberculosis(ET) is still relatively common disease in Korea. We intended to evaluate the length of endobronchial lesion, peribronchial thickness, luminal irregularity and associated mediastinal lymph node enlargement with Chest CT to get information for such aggressive treatment as electrocautery, laser therapy and so on of bronchial stricture in ET, and also to compare the change of Chest CT finding with that of bronchoscopic finding after one month of anti-tuberculosis treatment METHODS: We performed CT in 26 patients who were diagnosed as ET by bronchoscopy at Boramae Hospital from November 1991 to March 1996. After classifying El into seven subtypes according to bronchoscopio finding we analyzed the CT finding of each subtype. And we followed up the bronchoscopy, CT, arid PFT after one month of anti-tuberculosis treatment, and compared the change of CT findings with those of bronchoscopic findings in nine patients. RESULTS: Age of the patients was from 17 to 73 years old, arid the ratio of male to female was 1 : 25 with absolute female predominance. The site(s) of bronchial involvement by tuberculosis is one in 4 cases, two in nine cases arid three in one case, respectively, au] the left main bronchus was the most frequently involved site (13 cases for multiple involvements and 7 cases for single involvement among 26 cases). The length of bronchial involvement by tuberculosis which was measured by CT was from 10 to 55 mm, and there was a tendency that the lengh of involved lesion in fibrostenotic type was shorter than that of actively caseating type. Bronchial stricture on CT was noticed in 25 (96%) cases au] the range of severity was from total occlusion to near-normal and also showed wide variation even though the subtype of FT was same. The increase of peribronchial thickness which was measured by CT, was noticed in 21 cases (91 %) among 23 cases (in which the measurement was possible), and there was no improvement of peribronchial thickness in those cases which showed little improvement in bronchial stricture despite anti-tuberculosis treatment. There was no difference in the luminal irregularity of involved bronchi on CT in relation to bronchoscopic subtypes. The mediastinal lymph node enlargement, defined as the diameter of lymph node was larger than 1cm on CT, was detected in 20 cases (77%), and tight side was more frequently involved (L : R=1 : 52). The CT finding usually showed extrinsic bronchial compression but showed direct invasion in two cases which were bronchoscopically classified as tumorous typo. When follow-up bronchoscopy and UP was performed after one month of anti-tuberculosis treatment in nine patients, CT showed significant improvement in peribronchial thickness and mediastinal lymph node enlargement. Bronchial stricture was also improved in 6 cases but aggravated in 3 cases despite anti-tuberculosis therapy. In two cases which were classified as fibrostenotic type by bronchoscopy, CT showed significant improvement in bronchial stricture, interestingly. CONCLUSION: We concluded that the role of Chest CT was complimentary to bronchoscopy in FT. since CT was useful in evaluating the length of bronchial involvement peribronchial thickness, and mediestinal lymph node enlargement.